FIG. 1 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0029]

FIG. 2 is a schematic top view of a mesh according to an embodiment of the present disclosure. [0030]

FIG. 3 is a schematic illustration of a graphene sheet including a dopant according to an embodiment of the present disclosure. [0031]

FIG. 4 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0032]

FIGS. 5A and 5B are flow charts respectively illustrating a method of manufacturing a photocathode according to an embodiment of the present disclosure. [0033]

FIGS. 6A to 6D are schematic illustrations of a process of depositing a graphene layer on a substrate. [0034]

FIG. 7 illustrates a process condition (temperature profile and C H 4 and H 2 concentration) during the deposition of a single layer graphene sheet. [0035]

FIG. 8 shows the x-ray diffraction (XRD) pattern of a single crystalline Cu substrate. [0036]

FIG. 9 shows the XRD pattern of the (110) plane of Cu before and after the deposition of a graphene layer according to the conditions shown in

FIG. 10 shows the Raman spectrum of graphene. [0038]

FIG. 11 is an AFM image of the graphene layer coated on the Cu substrate utilizing the condition shown in

FIG. 12 shows the quantum efficiency of a Cu substrate, an annealed Cu substrate, a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 13 shows the quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 14 shows the normalized quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 15 is an optical image of the graphene layer-carrier substrate laminate taken from the graphene side. [0043]

FIG. 16A is a schematic illustration of a process for transferring a graphene sheet on a target substrate. [0044]

FIG. 17 is an optical image of a Ni mesh a) prior to the deposition of the graphene sheet, b) after the deposition of a five-sheet graphene layer, and c) after …

FIG. 18 shows optical images of a thick graphene layer. [0047]

FIG. 19 shows an optical image of a 40 nm thick graphene layer grown on a Ni substrate. [0048]

FIG. 20 is a Raman spectrum on the graphene layer shown in

FIG. 21 is a plot showing the effect of photon energy on the quantum efficiency of a photocathode with a five layer graphene sheet.

FIG. 1 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0029]

FIG. 2 is a schematic top view of a mesh according to an embodiment of the present disclosure. [0030]

FIG. 3 is a schematic illustration of a graphene sheet including a dopant according to an embodiment of the present disclosure. [0031]

FIG. 4 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0032]

FIGS. 5A and 5B are flow charts respectively illustrating a method of manufacturing a photocathode according to an embodiment of the present disclosure. [0033]

FIGS. 6A to 6D are schematic illustrations of a process of depositing a graphene layer on a substrate. [0034]

FIG. 7 illustrates a process condition (temperature profile and C H 4 and H 2 concentration) during the deposition of a single layer graphene sheet. [0035]

FIG. 8 shows the x-ray diffraction (XRD) pattern of a single crystalline Cu substrate. [0036]

FIG. 9 shows the XRD pattern of the (110) plane of Cu before and after the deposition of a graphene layer according to the conditions shown in

FIG. 10 shows the Raman spectrum of graphene. [0038]

FIG. 11 is an AFM image of the graphene layer coated on the Cu substrate utilizing the condition shown in

FIG. 12 shows the quantum efficiency of a Cu substrate, an annealed Cu substrate, a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 13 shows the quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 14 shows the normalized quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 15 is an optical image of the graphene layer-carrier substrate laminate taken from the graphene side. [0043]

FIG. 16A is a schematic illustration of a process for transferring a graphene sheet on a target substrate. [0044]

FIG. 17 is an optical image of a Ni mesh a) prior to the deposition of the graphene sheet, b) after the deposition of a five-sheet graphene layer, and c) after …

FIG. 18 shows optical images of a thick graphene layer. [0047]

FIG. 19 shows an optical image of a 40 nm thick graphene layer grown on a Ni substrate. [0048]

FIG. 20 is a Raman spectrum on the graphene layer shown in

FIG. 21 is a plot showing the effect of photon energy on the quantum efficiency of a photocathode with a five layer graphene sheet.

FIG. 1 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0029]

FIG. 2 is a schematic top view of a mesh according to an embodiment of the present disclosure. [0030]

FIG. 3 is a schematic illustration of a graphene sheet including a dopant according to an embodiment of the present disclosure. [0031]

FIG. 4 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0032]

FIGS. 5A and 5B are flow charts respectively illustrating a method of manufacturing a photocathode according to an embodiment of the present disclosure. [0033]

FIGS. 6A to 6D are schematic illustrations of a process of depositing a graphene layer on a substrate. [0034]

FIG. 7 illustrates a process condition (temperature profile and C H 4 and H 2 concentration) during the deposition of a single layer graphene sheet. [0035]

FIG. 8 shows the x-ray diffraction (XRD) pattern of a single crystalline Cu substrate. [0036]

FIG. 9 shows the XRD pattern of the (110) plane of Cu before and after the deposition of a graphene layer according to the conditions shown in

FIG. 10 shows the Raman spectrum of graphene. [0038]

FIG. 11 is an AFM image of the graphene layer coated on the Cu substrate utilizing the condition shown in

FIG. 12 shows the quantum efficiency of a Cu substrate, an annealed Cu substrate, a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 13 shows the quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 14 shows the normalized quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 15 is an optical image of the graphene layer-carrier substrate laminate taken from the graphene side. [0043]

FIG. 16A is a schematic illustration of a process for transferring a graphene sheet on a target substrate. [0044]

FIG. 17 is an optical image of a Ni mesh a) prior to the deposition of the graphene sheet, b) after the deposition of a five-sheet graphene layer, and c) after …

FIG. 18 shows optical images of a thick graphene layer. [0047]

FIG. 19 shows an optical image of a 40 nm thick graphene layer grown on a Ni substrate. [0048]

FIG. 20 is a Raman spectrum on the graphene layer shown in

FIG. 21 is a plot showing the effect of photon energy on the quantum efficiency of a photocathode with a five layer graphene sheet.

FIG. 1 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0029]

FIG. 2 is a schematic top view of a mesh according to an embodiment of the present disclosure. [0030]

FIG. 3 is a schematic illustration of a graphene sheet including a dopant according to an embodiment of the present disclosure. [0031]

FIG. 4 is a schematic cross sectional view of a photocathode according to an embodiment of the present disclosure. [0032]

FIGS. 5A and 5B are flow charts respectively illustrating a method of manufacturing a photocathode according to an embodiment of the present disclosure. [0033]

FIGS. 6A to 6D are schematic illustrations of a process of depositing a graphene layer on a substrate. [0034]

FIG. 7 illustrates a process condition (temperature profile and C H 4 and H 2 concentration) during the deposition of a single layer graphene sheet. [0035]

FIG. 8 shows the x-ray diffraction (XRD) pattern of a single crystalline Cu substrate. [0036]

FIG. 9 shows the XRD pattern of the (110) plane of Cu before and after the deposition of a graphene layer according to the conditions shown in

FIG. 10 shows the Raman spectrum of graphene. [0038]

FIG. 11 is an AFM image of the graphene layer coated on the Cu substrate utilizing the condition shown in

FIG. 12 shows the quantum efficiency of a Cu substrate, an annealed Cu substrate, a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 13 shows the quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 14 shows the normalized quantum efficiency of a Cu substrate and a graphene coated Cu substrate manufactured according to the conditions shown in

FIG. 15 is an optical image of the graphene layer-carrier substrate laminate taken from the graphene side. [0043]

FIG. 16A is a schematic illustration of a process for transferring a graphene sheet on a target substrate. [0044]

FIG. 17 is an optical image of a Ni mesh a) prior to the deposition of the graphene sheet, b) after the deposition of a five-sheet graphene layer, and c) after …

FIG. 18 shows optical images of a thick graphene layer. [0047]

FIG. 19 shows an optical image of a 40 nm thick graphene layer grown on a Ni substrate. [0048]

FIG. 20 is a Raman spectrum on the graphene layer shown in

FIG. 21 is a plot showing the effect of photon energy on the quantum efficiency of a photocathode with a five layer graphene sheet.