Patent
US 8,906,784GRAPHENE EPITAXIED ON SIC, WITH AN OPEN BAND GAP AND MOBILITY COMPARABLE TO STANDARD GRAPHENE WITH ZERO BAND GAP
Shirley Chiang
US
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US 8,906,784Patent drawings and their descriptions. Click a drawing to enlarge it.
Figures 3A, 3B, 3C and 3D are graphs in which the ordinates represent the logarithm of a measured intensity I, in nanoamperes, circulating in a graphene layer obtained by epitaxy and present on an SiC substrate, as a function of the applied voltage U in volts represented by the abscissas. Each …
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 4 shows the results obtained when observing a structure according to the first embodiment of the invention using the ARPES method. Only half of the dispersion of electronic states of the modified graphene layer was measured; this is sufficient because there is always perfect symmetry in the …
Figures 5 A and S C show advantageously this characteristic of epitaxied graphene present on a structure according to the invention.
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 2, in a structure 201 according to the invention, there is preferably atomic hydrogen present in the form of hydrogen atoms called added hydrogen atoms H between the modified graphene layer 23 and the substrate 21. The added hydrogen atoms H, that may be protium (i H isotope of hydrogen) or …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
Figures 7B to 7D are figures obtained using the ARPES method and represent the shape of the valency band of structures comprising one or more graphene layers. [00106] In these figures, the totality of the dispersion of electronic states was measured. This means that for a structure according to the …
Figure 7C shows a measurement of the structure according to the invention illustrated in figure 6A using the ARPES method, and also measured in
Figure 7D shows a measurement of the structure according to the invention shown in
Figure 6B, using the ARPES method. A third valency band V₃ in the form of a Dirac cone can be seen, located between the first and the second valency bands V 1 and V2. The first valency band V 1 is then clearly separated from the conducting cone C. The first valency band is located at 0.4 eV from the …
Figures 8A to 8 E:-firstly, an initial structure 800 comprising a standard graphene layer 82 present on a semiconducting or insulating substrate 81 has to be provided, like that shown in
Figure 8B, added hydrogen atoms H composed of atomic hydrogen, are deposited on the initial structure 800 and then interact with it to form a-31-Docket No. 434299-1073 modified graphene layer 83, shown in
Figure 8C, starting from the standard graphene layer 82. Thus, the result obtained is a modified structure 801. [00117] Most added hydrogen atoms H create chemical bonds 84 with the substrate 81. The added hydrogen atoms H then advantageously form a buffer layer composed of atomic hydrogen between …
Figure 8D, identical to
Figure 8 E. The post-hydrogenation annealing 86 ' is at a temperature between 200 ° C and 400 ° C, preferably between 250 ° C and 350 0 and in particular close to 300 °C, and lasts for a few minutes, for example between one minute and 20 minutes and advantageously five minutes. For example, it may …
Figure 9B) above the silicon substrate 90, or the formation of SiC by any other known method such as an ultravacuum furnace, sublimation of a neutral gas under pressure, etc.;-36-Docket No. 434299-1073-formation of a standard graphene layer 92 on the surface layer 91 made of SiC present on the …
Figure 9C). [00137] The silicon substrate 90 and therefore the surface layer 91 made of SiC may have a (100), (110) or (111) orientation. [00138] Such a method is advantageous because it is easy to obtain large silicon substrates 90. Therefore it is possible and relatively easy to produce …
Figures 12A to 12C. This second advantageous embodiment of the method according to the invention is a variant of the first advantageous embodiment of the method according to the invention in which exposure doses to hydrogen gas are different. [00141] When an initial structure 1201 according to the …
Figure 12B is done at a higher exposure dose, for example between 1300 Langmuirs and 4000 Langmuirs, added hydrogen atoms H penetrate under the initial graphene layer 123 and form a buffer of added hydrogen atoms H. This buffer, during annealing 126 according to the invention, decouples the last …
Figure 12C). Therefore, the end result is a final structure 1200 comprising a substrate 120, an SiC surface layer 129 from which at least one carbon plane and part of a silicon plane that were on the initial structure 1201 have been removed, and a double modified graphene layer 1230 that may extend …
Figure 11. This figure shows the central emission spot 110 and six peripheral spots 111 to 116. If there had been a rotation of 30 0 as in the case of a standard graphene layer on an SiC substrate, these peripheral spots would all have at least one 6 l 3x6 l 3 satellite spot. Since there is no 6 l …
Figure 10, reproducing an STM observation of such a structure. In particular, the method according to the invention can be applied if there are any existing critical defects 102 between the SiC substrate and the modified graphene layer. [00167] Surface defects in the SiC substrate do not cause any …
Figures 13A to 13C.-45-Docket No. 434299-1073 [00176] The first and second advantageous embodiments of the method according to the invention require an initial structure comprising at least one substrate on which an initial epitaxied graphene layer is present on the surface. [00177] The inventors …
Figure 13B). In particular, hydrogenation is preferably done with a hydrogen gas exposure dose between 1500 Langmuirs and 2500 Langmuirs or more than 2500 Langmuirs, for example 2000 Langmuirs or 2200 Langmuirs or 3000 Langmuirs. These values should be considered under pressure conditions equal to …
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
Method of manufacturing a structure comprising at least one modified semiconducting graphene layer, the modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and with a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS), the dispersion of electronic states being either a valency band forming a Dirac cone or a linear dispersion of electronic states, the modified graphene layer being present on a substrate, comprising the following steps:-supply of an initial structure comprising at least one non-metallic substrate capable of supporting a graphene layer,-formation of a graphene layer on the substrate, wherein the gr aphene la yer covers the totality of a surface of the substrate,-hydrogenation of the initial structure by exposure to atomic hydrogen, to obtain the modified graphene layer, with an exposure dose between 100 Langmuirs and 4000 Langmuirs, namely between 13 mPa.s and 533 mPa.s.
Method according to claim 1, in which the hydrogenation step takes place after the formation of the graphene layer. Page 2 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826117.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the exposure dose being between 1300 and 2500 Langmuirs or between 1300 and 4000 Langmuirs, namely between 173 mPa.s and 333 mPa.s or between 173 mPa.s and 533 mPa.s, at least one last carbon plane being decoupled from the SiC surface layer, thus forming at least one semiconducting modified graphene layer with a valency band with the shape of a Dirac cone or a linear dispersion of electronic states.
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the substrate originating from a silicon substrate.
Method according to claim 1, comprising annealing that takes place after the hydrogenation step, called post-hydrogenation annealing at a temperature between 200 ° C and 400 ° C, lasting between one minute and twenty minutes.
Method according to claim 1, comprising annealing taking place during the hydrogenation step, called hydrogenation annealing at a temperature between 200 ° C and 400 °C. Page 3 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826118.2.1730.207.2245.292.svg 0.283 1.717 Chemistry Black and white PATENT
Method according to claim 1, in which the hydrogenation step takes place at a pressure less than 10- 4 Pascals.
Structure comprising at least one semiconducting or insulating substrate, and at least one graphene layer present on this substrate, wherein the graphene layer is a semiconducting modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and in that it has a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS) in the form of either a valency band forming a Dirac cone or a linear dispersion of electronic states.
Structure according to claim 9, in which added hydrogen atoms (H) form a buffer plane between the modified graphene layer and the SiC substrate, and the added hydrogen atoms (H) are bonded to the SiC of the substrate.
Structure according to claim 9, in which several graphene layers are stacked on each other, and are decoupled from each other electronically.
Structure according to claim 9, comprising several graphene layers, including a first semiconducting modified graphene layer with a band gap of more than 0.2 eV and with a valency band forming a Dirac cone or a linear dispersion of electronic states, and a second graphene layer with an almost metallic or semiconducting behaviour layer with a zero band gap and separated from the substrate by the first graphene layer. Page 4 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826119.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
. canceled
Layer stacks claimed or described, ordered top of device to substrate.
hydrogenated graphene on SiC structure
Materials described outside the worked examples.
modified semiconducting graphene layer
graphene layer (unmodified/precursor)
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
band gap of modified semiconducting graphene layer (claimed range) | 0.2–1.8 | modified semiconducting graphene layer |
band gap of modified semiconducting graphene layer (description embodiment, up to 1.3 eV) |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
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US 8,906,784Patent drawings and their descriptions. Click a drawing to enlarge it.
Figures 3A, 3B, 3C and 3D are graphs in which the ordinates represent the logarithm of a measured intensity I, in nanoamperes, circulating in a graphene layer obtained by epitaxy and present on an SiC substrate, as a function of the applied voltage U in volts represented by the abscissas. Each …
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 4 shows the results obtained when observing a structure according to the first embodiment of the invention using the ARPES method. Only half of the dispersion of electronic states of the modified graphene layer was measured; this is sufficient because there is always perfect symmetry in the …
Figures 5 A and S C show advantageously this characteristic of epitaxied graphene present on a structure according to the invention.
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 2, in a structure 201 according to the invention, there is preferably atomic hydrogen present in the form of hydrogen atoms called added hydrogen atoms H between the modified graphene layer 23 and the substrate 21. The added hydrogen atoms H, that may be protium (i H isotope of hydrogen) or …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
Figures 7B to 7D are figures obtained using the ARPES method and represent the shape of the valency band of structures comprising one or more graphene layers. [00106] In these figures, the totality of the dispersion of electronic states was measured. This means that for a structure according to the …
Figure 7C shows a measurement of the structure according to the invention illustrated in figure 6A using the ARPES method, and also measured in
Figure 7D shows a measurement of the structure according to the invention shown in
Figure 6B, using the ARPES method. A third valency band V₃ in the form of a Dirac cone can be seen, located between the first and the second valency bands V 1 and V2. The first valency band V 1 is then clearly separated from the conducting cone C. The first valency band is located at 0.4 eV from the …
Figures 8A to 8 E:-firstly, an initial structure 800 comprising a standard graphene layer 82 present on a semiconducting or insulating substrate 81 has to be provided, like that shown in
Figure 8B, added hydrogen atoms H composed of atomic hydrogen, are deposited on the initial structure 800 and then interact with it to form a-31-Docket No. 434299-1073 modified graphene layer 83, shown in
Figure 8C, starting from the standard graphene layer 82. Thus, the result obtained is a modified structure 801. [00117] Most added hydrogen atoms H create chemical bonds 84 with the substrate 81. The added hydrogen atoms H then advantageously form a buffer layer composed of atomic hydrogen between …
Figure 8D, identical to
Figure 8 E. The post-hydrogenation annealing 86 ' is at a temperature between 200 ° C and 400 ° C, preferably between 250 ° C and 350 0 and in particular close to 300 °C, and lasts for a few minutes, for example between one minute and 20 minutes and advantageously five minutes. For example, it may …
Figure 9B) above the silicon substrate 90, or the formation of SiC by any other known method such as an ultravacuum furnace, sublimation of a neutral gas under pressure, etc.;-36-Docket No. 434299-1073-formation of a standard graphene layer 92 on the surface layer 91 made of SiC present on the …
Figure 9C). [00137] The silicon substrate 90 and therefore the surface layer 91 made of SiC may have a (100), (110) or (111) orientation. [00138] Such a method is advantageous because it is easy to obtain large silicon substrates 90. Therefore it is possible and relatively easy to produce …
Figures 12A to 12C. This second advantageous embodiment of the method according to the invention is a variant of the first advantageous embodiment of the method according to the invention in which exposure doses to hydrogen gas are different. [00141] When an initial structure 1201 according to the …
Figure 12B is done at a higher exposure dose, for example between 1300 Langmuirs and 4000 Langmuirs, added hydrogen atoms H penetrate under the initial graphene layer 123 and form a buffer of added hydrogen atoms H. This buffer, during annealing 126 according to the invention, decouples the last …
Figure 12C). Therefore, the end result is a final structure 1200 comprising a substrate 120, an SiC surface layer 129 from which at least one carbon plane and part of a silicon plane that were on the initial structure 1201 have been removed, and a double modified graphene layer 1230 that may extend …
Figure 11. This figure shows the central emission spot 110 and six peripheral spots 111 to 116. If there had been a rotation of 30 0 as in the case of a standard graphene layer on an SiC substrate, these peripheral spots would all have at least one 6 l 3x6 l 3 satellite spot. Since there is no 6 l …
Figure 10, reproducing an STM observation of such a structure. In particular, the method according to the invention can be applied if there are any existing critical defects 102 between the SiC substrate and the modified graphene layer. [00167] Surface defects in the SiC substrate do not cause any …
Figures 13A to 13C.-45-Docket No. 434299-1073 [00176] The first and second advantageous embodiments of the method according to the invention require an initial structure comprising at least one substrate on which an initial epitaxied graphene layer is present on the surface. [00177] The inventors …
Figure 13B). In particular, hydrogenation is preferably done with a hydrogen gas exposure dose between 1500 Langmuirs and 2500 Langmuirs or more than 2500 Langmuirs, for example 2000 Langmuirs or 2200 Langmuirs or 3000 Langmuirs. These values should be considered under pressure conditions equal to …
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
Method of manufacturing a structure comprising at least one modified semiconducting graphene layer, the modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and with a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS), the dispersion of electronic states being either a valency band forming a Dirac cone or a linear dispersion of electronic states, the modified graphene layer being present on a substrate, comprising the following steps:-supply of an initial structure comprising at least one non-metallic substrate capable of supporting a graphene layer,-formation of a graphene layer on the substrate, wherein the gr aphene la yer covers the totality of a surface of the substrate,-hydrogenation of the initial structure by exposure to atomic hydrogen, to obtain the modified graphene layer, with an exposure dose between 100 Langmuirs and 4000 Langmuirs, namely between 13 mPa.s and 533 mPa.s.
Method according to claim 1, in which the hydrogenation step takes place after the formation of the graphene layer. Page 2 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826117.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the exposure dose being between 1300 and 2500 Langmuirs or between 1300 and 4000 Langmuirs, namely between 173 mPa.s and 333 mPa.s or between 173 mPa.s and 533 mPa.s, at least one last carbon plane being decoupled from the SiC surface layer, thus forming at least one semiconducting modified graphene layer with a valency band with the shape of a Dirac cone or a linear dispersion of electronic states.
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the substrate originating from a silicon substrate.
Method according to claim 1, comprising annealing that takes place after the hydrogenation step, called post-hydrogenation annealing at a temperature between 200 ° C and 400 ° C, lasting between one minute and twenty minutes.
Method according to claim 1, comprising annealing taking place during the hydrogenation step, called hydrogenation annealing at a temperature between 200 ° C and 400 °C. Page 3 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826118.2.1730.207.2245.292.svg 0.283 1.717 Chemistry Black and white PATENT
Method according to claim 1, in which the hydrogenation step takes place at a pressure less than 10- 4 Pascals.
Structure comprising at least one semiconducting or insulating substrate, and at least one graphene layer present on this substrate, wherein the graphene layer is a semiconducting modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and in that it has a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS) in the form of either a valency band forming a Dirac cone or a linear dispersion of electronic states.
Structure according to claim 9, in which added hydrogen atoms (H) form a buffer plane between the modified graphene layer and the SiC substrate, and the added hydrogen atoms (H) are bonded to the SiC of the substrate.
Structure according to claim 9, in which several graphene layers are stacked on each other, and are decoupled from each other electronically.
Structure according to claim 9, comprising several graphene layers, including a first semiconducting modified graphene layer with a band gap of more than 0.2 eV and with a valency band forming a Dirac cone or a linear dispersion of electronic states, and a second graphene layer with an almost metallic or semiconducting behaviour layer with a zero band gap and separated from the substrate by the first graphene layer. Page 4 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826119.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
. canceled
Layer stacks claimed or described, ordered top of device to substrate.
hydrogenated graphene on SiC structure
Materials described outside the worked examples.
modified semiconducting graphene layer
graphene layer (unmodified/precursor)
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
band gap of modified semiconducting graphene layer (claimed range) | 0.2–1.8 | modified semiconducting graphene layer |
band gap of modified semiconducting graphene layer (description embodiment, up to 1.3 eV) |
Related documents with shared materials, methods, properties, or citations.
Patent
Atlas literature
Patent
US 8,906,784Patent drawings and their descriptions. Click a drawing to enlarge it.
Figures 3A, 3B, 3C and 3D are graphs in which the ordinates represent the logarithm of a measured intensity I, in nanoamperes, circulating in a graphene layer obtained by epitaxy and present on an SiC substrate, as a function of the applied voltage U in volts represented by the abscissas. Each …
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 4 shows the results obtained when observing a structure according to the first embodiment of the invention using the ARPES method. Only half of the dispersion of electronic states of the modified graphene layer was measured; this is sufficient because there is always perfect symmetry in the …
Figures 5 A and S C show advantageously this characteristic of epitaxied graphene present on a structure according to the invention.
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 2, in a structure 201 according to the invention, there is preferably atomic hydrogen present in the form of hydrogen atoms called added hydrogen atoms H between the modified graphene layer 23 and the substrate 21. The added hydrogen atoms H, that may be protium (i H isotope of hydrogen) or …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
Figures 7B to 7D are figures obtained using the ARPES method and represent the shape of the valency band of structures comprising one or more graphene layers. [00106] In these figures, the totality of the dispersion of electronic states was measured. This means that for a structure according to the …
Figure 7C shows a measurement of the structure according to the invention illustrated in figure 6A using the ARPES method, and also measured in
Figure 7D shows a measurement of the structure according to the invention shown in
Figure 6B, using the ARPES method. A third valency band V₃ in the form of a Dirac cone can be seen, located between the first and the second valency bands V 1 and V2. The first valency band V 1 is then clearly separated from the conducting cone C. The first valency band is located at 0.4 eV from the …
Figures 8A to 8 E:-firstly, an initial structure 800 comprising a standard graphene layer 82 present on a semiconducting or insulating substrate 81 has to be provided, like that shown in
Figure 8B, added hydrogen atoms H composed of atomic hydrogen, are deposited on the initial structure 800 and then interact with it to form a-31-Docket No. 434299-1073 modified graphene layer 83, shown in
Figure 8C, starting from the standard graphene layer 82. Thus, the result obtained is a modified structure 801. [00117] Most added hydrogen atoms H create chemical bonds 84 with the substrate 81. The added hydrogen atoms H then advantageously form a buffer layer composed of atomic hydrogen between …
Figure 8D, identical to
Figure 8 E. The post-hydrogenation annealing 86 ' is at a temperature between 200 ° C and 400 ° C, preferably between 250 ° C and 350 0 and in particular close to 300 °C, and lasts for a few minutes, for example between one minute and 20 minutes and advantageously five minutes. For example, it may …
Figure 9B) above the silicon substrate 90, or the formation of SiC by any other known method such as an ultravacuum furnace, sublimation of a neutral gas under pressure, etc.;-36-Docket No. 434299-1073-formation of a standard graphene layer 92 on the surface layer 91 made of SiC present on the …
Figure 9C). [00137] The silicon substrate 90 and therefore the surface layer 91 made of SiC may have a (100), (110) or (111) orientation. [00138] Such a method is advantageous because it is easy to obtain large silicon substrates 90. Therefore it is possible and relatively easy to produce …
Figures 12A to 12C. This second advantageous embodiment of the method according to the invention is a variant of the first advantageous embodiment of the method according to the invention in which exposure doses to hydrogen gas are different. [00141] When an initial structure 1201 according to the …
Figure 12B is done at a higher exposure dose, for example between 1300 Langmuirs and 4000 Langmuirs, added hydrogen atoms H penetrate under the initial graphene layer 123 and form a buffer of added hydrogen atoms H. This buffer, during annealing 126 according to the invention, decouples the last …
Figure 12C). Therefore, the end result is a final structure 1200 comprising a substrate 120, an SiC surface layer 129 from which at least one carbon plane and part of a silicon plane that were on the initial structure 1201 have been removed, and a double modified graphene layer 1230 that may extend …
Figure 11. This figure shows the central emission spot 110 and six peripheral spots 111 to 116. If there had been a rotation of 30 0 as in the case of a standard graphene layer on an SiC substrate, these peripheral spots would all have at least one 6 l 3x6 l 3 satellite spot. Since there is no 6 l …
Figure 10, reproducing an STM observation of such a structure. In particular, the method according to the invention can be applied if there are any existing critical defects 102 between the SiC substrate and the modified graphene layer. [00167] Surface defects in the SiC substrate do not cause any …
Figures 13A to 13C.-45-Docket No. 434299-1073 [00176] The first and second advantageous embodiments of the method according to the invention require an initial structure comprising at least one substrate on which an initial epitaxied graphene layer is present on the surface. [00177] The inventors …
Figure 13B). In particular, hydrogenation is preferably done with a hydrogen gas exposure dose between 1500 Langmuirs and 2500 Langmuirs or more than 2500 Langmuirs, for example 2000 Langmuirs or 2200 Langmuirs or 3000 Langmuirs. These values should be considered under pressure conditions equal to …
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
Method of manufacturing a structure comprising at least one modified semiconducting graphene layer, the modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and with a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS), the dispersion of electronic states being either a valency band forming a Dirac cone or a linear dispersion of electronic states, the modified graphene layer being present on a substrate, comprising the following steps:-supply of an initial structure comprising at least one non-metallic substrate capable of supporting a graphene layer,-formation of a graphene layer on the substrate, wherein the gr aphene la yer covers the totality of a surface of the substrate,-hydrogenation of the initial structure by exposure to atomic hydrogen, to obtain the modified graphene layer, with an exposure dose between 100 Langmuirs and 4000 Langmuirs, namely between 13 mPa.s and 533 mPa.s.
Method according to claim 1, in which the hydrogenation step takes place after the formation of the graphene layer. Page 2 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826117.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the exposure dose being between 1300 and 2500 Langmuirs or between 1300 and 4000 Langmuirs, namely between 173 mPa.s and 333 mPa.s or between 173 mPa.s and 533 mPa.s, at least one last carbon plane being decoupled from the SiC surface layer, thus forming at least one semiconducting modified graphene layer with a valency band with the shape of a Dirac cone or a linear dispersion of electronic states.
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the substrate originating from a silicon substrate.
Method according to claim 1, comprising annealing that takes place after the hydrogenation step, called post-hydrogenation annealing at a temperature between 200 ° C and 400 ° C, lasting between one minute and twenty minutes.
Method according to claim 1, comprising annealing taking place during the hydrogenation step, called hydrogenation annealing at a temperature between 200 ° C and 400 °C. Page 3 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826118.2.1730.207.2245.292.svg 0.283 1.717 Chemistry Black and white PATENT
Method according to claim 1, in which the hydrogenation step takes place at a pressure less than 10- 4 Pascals.
Structure comprising at least one semiconducting or insulating substrate, and at least one graphene layer present on this substrate, wherein the graphene layer is a semiconducting modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and in that it has a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS) in the form of either a valency band forming a Dirac cone or a linear dispersion of electronic states.
Structure according to claim 9, in which added hydrogen atoms (H) form a buffer plane between the modified graphene layer and the SiC substrate, and the added hydrogen atoms (H) are bonded to the SiC of the substrate.
Structure according to claim 9, in which several graphene layers are stacked on each other, and are decoupled from each other electronically.
Structure according to claim 9, comprising several graphene layers, including a first semiconducting modified graphene layer with a band gap of more than 0.2 eV and with a valency band forming a Dirac cone or a linear dispersion of electronic states, and a second graphene layer with an almost metallic or semiconducting behaviour layer with a zero band gap and separated from the substrate by the first graphene layer. Page 4 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826119.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
. canceled
Layer stacks claimed or described, ordered top of device to substrate.
hydrogenated graphene on SiC structure
Materials described outside the worked examples.
modified semiconducting graphene layer
graphene layer (unmodified/precursor)
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
band gap of modified semiconducting graphene layer (claimed range) | 0.2–1.8 | modified semiconducting graphene layer |
band gap of modified semiconducting graphene layer (description embodiment, up to 1.3 eV) |
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US 8,906,784Patent drawings and their descriptions. Click a drawing to enlarge it.
Figures 3A, 3B, 3C and 3D are graphs in which the ordinates represent the logarithm of a measured intensity I, in nanoamperes, circulating in a graphene layer obtained by epitaxy and present on an SiC substrate, as a function of the applied voltage U in volts represented by the abscissas. Each …
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 4 shows the results obtained when observing a structure according to the first embodiment of the invention using the ARPES method. Only half of the dispersion of electronic states of the modified graphene layer was measured; this is sufficient because there is always perfect symmetry in the …
Figures 5 A and S C show advantageously this characteristic of epitaxied graphene present on a structure according to the invention.
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 2, in a structure 201 according to the invention, there is preferably atomic hydrogen present in the form of hydrogen atoms called added hydrogen atoms H between the modified graphene layer 23 and the substrate 21. The added hydrogen atoms H, that may be protium (i H isotope of hydrogen) or …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
Figures 7B to 7D are figures obtained using the ARPES method and represent the shape of the valency band of structures comprising one or more graphene layers. [00106] In these figures, the totality of the dispersion of electronic states was measured. This means that for a structure according to the …
Figure 7C shows a measurement of the structure according to the invention illustrated in figure 6A using the ARPES method, and also measured in
Figure 7D shows a measurement of the structure according to the invention shown in
Figure 6B, using the ARPES method. A third valency band V₃ in the form of a Dirac cone can be seen, located between the first and the second valency bands V 1 and V2. The first valency band V 1 is then clearly separated from the conducting cone C. The first valency band is located at 0.4 eV from the …
Figures 8A to 8 E:-firstly, an initial structure 800 comprising a standard graphene layer 82 present on a semiconducting or insulating substrate 81 has to be provided, like that shown in
Figure 8B, added hydrogen atoms H composed of atomic hydrogen, are deposited on the initial structure 800 and then interact with it to form a-31-Docket No. 434299-1073 modified graphene layer 83, shown in
Figure 8C, starting from the standard graphene layer 82. Thus, the result obtained is a modified structure 801. [00117] Most added hydrogen atoms H create chemical bonds 84 with the substrate 81. The added hydrogen atoms H then advantageously form a buffer layer composed of atomic hydrogen between …
Figure 8D, identical to
Figure 8 E. The post-hydrogenation annealing 86 ' is at a temperature between 200 ° C and 400 ° C, preferably between 250 ° C and 350 0 and in particular close to 300 °C, and lasts for a few minutes, for example between one minute and 20 minutes and advantageously five minutes. For example, it may …
Figure 9B) above the silicon substrate 90, or the formation of SiC by any other known method such as an ultravacuum furnace, sublimation of a neutral gas under pressure, etc.;-36-Docket No. 434299-1073-formation of a standard graphene layer 92 on the surface layer 91 made of SiC present on the …
Figure 9C). [00137] The silicon substrate 90 and therefore the surface layer 91 made of SiC may have a (100), (110) or (111) orientation. [00138] Such a method is advantageous because it is easy to obtain large silicon substrates 90. Therefore it is possible and relatively easy to produce …
Figures 12A to 12C. This second advantageous embodiment of the method according to the invention is a variant of the first advantageous embodiment of the method according to the invention in which exposure doses to hydrogen gas are different. [00141] When an initial structure 1201 according to the …
Figure 12B is done at a higher exposure dose, for example between 1300 Langmuirs and 4000 Langmuirs, added hydrogen atoms H penetrate under the initial graphene layer 123 and form a buffer of added hydrogen atoms H. This buffer, during annealing 126 according to the invention, decouples the last …
Figure 12C). Therefore, the end result is a final structure 1200 comprising a substrate 120, an SiC surface layer 129 from which at least one carbon plane and part of a silicon plane that were on the initial structure 1201 have been removed, and a double modified graphene layer 1230 that may extend …
Figure 11. This figure shows the central emission spot 110 and six peripheral spots 111 to 116. If there had been a rotation of 30 0 as in the case of a standard graphene layer on an SiC substrate, these peripheral spots would all have at least one 6 l 3x6 l 3 satellite spot. Since there is no 6 l …
Figure 10, reproducing an STM observation of such a structure. In particular, the method according to the invention can be applied if there are any existing critical defects 102 between the SiC substrate and the modified graphene layer. [00167] Surface defects in the SiC substrate do not cause any …
Figures 13A to 13C.-45-Docket No. 434299-1073 [00176] The first and second advantageous embodiments of the method according to the invention require an initial structure comprising at least one substrate on which an initial epitaxied graphene layer is present on the surface. [00177] The inventors …
Figure 13B). In particular, hydrogenation is preferably done with a hydrogen gas exposure dose between 1500 Langmuirs and 2500 Langmuirs or more than 2500 Langmuirs, for example 2000 Langmuirs or 2200 Langmuirs or 3000 Langmuirs. These values should be considered under pressure conditions equal to …
Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.
Method of manufacturing a structure comprising at least one modified semiconducting graphene layer, the modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and with a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS), the dispersion of electronic states being either a valency band forming a Dirac cone or a linear dispersion of electronic states, the modified graphene layer being present on a substrate, comprising the following steps:-supply of an initial structure comprising at least one non-metallic substrate capable of supporting a graphene layer,-formation of a graphene layer on the substrate, wherein the gr aphene la yer covers the totality of a surface of the substrate,-hydrogenation of the initial structure by exposure to atomic hydrogen, to obtain the modified graphene layer, with an exposure dose between 100 Langmuirs and 4000 Langmuirs, namely between 13 mPa.s and 533 mPa.s.
Method according to claim 1, in which the hydrogenation step takes place after the formation of the graphene layer. Page 2 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826117.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the exposure dose being between 1300 and 2500 Langmuirs or between 1300 and 4000 Langmuirs, namely between 173 mPa.s and 333 mPa.s or between 173 mPa.s and 533 mPa.s, at least one last carbon plane being decoupled from the SiC surface layer, thus forming at least one semiconducting modified graphene layer with a valency band with the shape of a Dirac cone or a linear dispersion of electronic states.
Method according to claim 1, in which at least one surface layer of the substrate is made of SiC, the substrate originating from a silicon substrate.
Method according to claim 1, comprising annealing that takes place after the hydrogenation step, called post-hydrogenation annealing at a temperature between 200 ° C and 400 ° C, lasting between one minute and twenty minutes.
Method according to claim 1, comprising annealing taking place during the hydrogenation step, called hydrogenation annealing at a temperature between 200 ° C and 400 °C. Page 3 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826118.2.1730.207.2245.292.svg 0.283 1.717 Chemistry Black and white PATENT
Method according to claim 1, in which the hydrogenation step takes place at a pressure less than 10- 4 Pascals.
Structure comprising at least one semiconducting or insulating substrate, and at least one graphene layer present on this substrate, wherein the graphene layer is a semiconducting modified graphene layer comprising a band gap between 0.2 eV and 1.8 eV, measured by scanning tunneling spectroscopy, and in that it has a dispersion of electronic states, observed by Angle Resolved PhotoEmission Spectroscopy (ARPES or ARUPS) in the form of either a valency band forming a Dirac cone or a linear dispersion of electronic states.
Structure according to claim 9, in which added hydrogen atoms (H) form a buffer plane between the modified graphene layer and the SiC substrate, and the added hydrogen atoms (H) are bonded to the SiC of the substrate.
Structure according to claim 9, in which several graphene layers are stacked on each other, and are decoupled from each other electronically.
Structure according to claim 9, comprising several graphene layers, including a first semiconducting modified graphene layer with a band gap of more than 0.2 eV and with a valency band forming a Dirac cone or a linear dispersion of electronic states, and a second graphene layer with an almost metallic or semiconducting behaviour layer with a zero band gap and separated from the substrate by the first graphene layer. Page 4 of 9 SVG 13508343.07-15-2014.HXMPYB₅BPXXIFW3.CLM21826119.2.1730.207.2245.292.svg 0.283 1.717 Graph Black and white PATENT
. canceled
Layer stacks claimed or described, ordered top of device to substrate.
hydrogenated graphene on SiC structure
Materials described outside the worked examples.
modified semiconducting graphene layer
graphene layer (unmodified/precursor)
Additional fabrication and treatment steps described in the patent.
Measurements and analyses referenced in the patent, with their drawing references.
Figure 3B shows a measurement obtained by STS of the band gap 7B of a modified graphene layer present in a structure according to a second particular embodiment of the invention. The band gap 7B, the difference between the smallest positive voltage U l at which the current can pass and the smallest …
Performance values and ranges asserted in the specification or claims.
| Property | Value | Material |
|---|---|---|
band gap of modified semiconducting graphene layer (claimed range) | 0.2–1.8 | modified semiconducting graphene layer |
band gap of modified semiconducting graphene layer (description embodiment, up to 1.3 eV) |
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silicon carbide substrate
SiC
silicon substrate
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Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
modified semiconducting graphene layer |
band gap opening from hydrogenation on iridium (prior art, STS) | 0.45 | — |
— | 0.1–0.7 eV | — |
— | 0.7–2 eV | — |
— | 0.2–1.8 eV | — |
Temperature | 200–400 °C | — |
Pressure | 0.000001 torr | — |
Pressure | 0–4 Pa | — |
Pressure | 0.000001 Pa | — |
— | ≤ 0.05 eV | — |
— | ≤ 0.1 eV | — |
— | ≥ 2 eV | — |
— | ≥ 0.2 eV | — |
Pressure | ≤ 0.0001 Pa | — |
silicon carbide substrate
SiC
silicon substrate
Si
atomic hydrogen
H
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
modified semiconducting graphene layer |
band gap opening from hydrogenation on iridium (prior art, STS) | 0.45 | — |
— | 0.1–0.7 eV | — |
— | 0.7–2 eV | — |
— | 0.2–1.8 eV | — |
Temperature | 200–400 °C | — |
Pressure | 0.000001 torr | — |
Pressure | 0–4 Pa | — |
Pressure | 0.000001 Pa | — |
— | ≤ 0.05 eV | — |
— | ≤ 0.1 eV | — |
— | ≥ 2 eV | — |
— | ≥ 0.2 eV | — |
Pressure | ≤ 0.0001 Pa | — |
silicon carbide substrate
SiC
silicon substrate
Si
atomic hydrogen
H
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
modified semiconducting graphene layer |
band gap opening from hydrogenation on iridium (prior art, STS) | 0.45 | — |
— | 0.1–0.7 eV | — |
— | 0.7–2 eV | — |
— | 0.2–1.8 eV | — |
Temperature | 200–400 °C | — |
Pressure | 0.000001 torr | — |
Pressure | 0–4 Pa | — |
Pressure | 0.000001 Pa | — |
— | ≤ 0.05 eV | — |
— | ≤ 0.1 eV | — |
— | ≥ 2 eV | — |
— | ≥ 0.2 eV | — |
Pressure | ≤ 0.0001 Pa | — |
silicon carbide substrate
SiC
silicon substrate
Si
atomic hydrogen
H
Figure 3C shows a measurement obtained by STS of the band gap 7C of a modified graphene layer present in a structure according to a third particular embodiment of the invention. The band gap 7C, the difference between the smallest positive voltage U l at which current passes and the smallest negative …
Figure 3D shows this measurement of the band gap of a standard epitaxied graphene layer. In this figure, an intensity is produced for any applied voltage U. Therefore, it is assumed that the band gap is zero. [0081] In these figures, as in figure 3A, the Fermi level located at zero voltage is closer …
Figure 5 C is an STM map of a structure according to the first embodiment of the invention, comprising a modified graphene layer present on an SiC substrate, with a band gap measured by S T S as being 1.3 eV. The inset in this figure clearly shows that there is a ho neycomb lattice 11 made of …
Figure 6A). The set of several modified epitaxied graphene layers 63, 63' according to the invention is semiconducting with an open band gap and has a linear dispersion of electronic states. [00101] Therefore, it can be understood that the invention also relates to a structure comprising two modified …
Figure 7A shows an S T S measurement of the graphene band gap 7 ' in a structure comprising two superposed layers of modified graphene present on the carbon face of an SiC substrate in a structure according to the invention, with no defects between the modified graphene layer and the substrate. It …
modified semiconducting graphene layer |
band gap opening from hydrogenation on iridium (prior art, STS) | 0.45 | — |
— | 0.1–0.7 eV | — |
— | 0.7–2 eV | — |
— | 0.2–1.8 eV | — |
Temperature | 200–400 °C | — |
Pressure | 0.000001 torr | — |
Pressure | 0–4 Pa | — |
Pressure | 0.000001 Pa | — |
— | ≤ 0.05 eV | — |
— | ≤ 0.1 eV | — |
— | ≥ 2 eV | — |
— | ≥ 0.2 eV | — |
Pressure | ≤ 0.0001 Pa | — |