Abstract

Here, we report a full-fledged journey towards the material synthesis and characterization of a few-layered/thin WSe₂ using sputtered W-films on SiO₂/Si substrates followed by electrical studies under dark and illumination conditions. Growth temperature of 500oC and a gas flow rate of 55 sccm are found to be the optimized parameters for the formation of thermodynamically stable WSe₂ with dominant Raman peak at 265 cm⁻¹. XRD and HR-TEM measurements clarify the formation of high crystallinity along the c-axis and quasi-crystallinity along a and b axes, respectively. Lower intensities from Raman-measurement and PL-peak at 768 nm (with 532 nm excitation wavelength) infers the thin nature of the grown film. This work also re-tracks the controlled etching by reactive ions to achieve large area bi/tri-layer films to fabricate high performance devices. An advanced dual MOS (DMOS) structure on SiO₂/p-Si substrate is fabricated which shows tremendous performance by means of photo-capacitance under illumination condition where photo-carriers can survive the higher probe frequencies. Under illumination conditions, the DMOS device demonstrates superior performance, exhibiting a significantly strong electron-inversion region compared to HfO₂/SiO₂/p-Si and SiO₂/p-Si MOS devices, even at high frequencies (1-10 MHz). This work thus presents a potential approach for capacitance-based, highly sensitive photodetection within conventional Si technology, enabled by integrating WSe₂/W as the active material.

Abstract

Here, we report a full-fledged journey towards the material synthesis and characterization of a few-layered/thin WSe₂ using sputtered W-films on SiO₂/Si substrates followed by electrical studies under dark and illumination conditions. Growth temperature of 500oC and a gas flow rate of 55 sccm are found to be the optimized parameters for the formation of thermodynamically stable WSe₂ with dominant Raman peak at 265 cm⁻¹. XRD and HR-TEM measurements clarify the formation of high crystallinity along the c-axis and quasi-crystallinity along a and b axes, respectively. Lower intensities from Raman-measurement and PL-peak at 768 nm (with 532 nm excitation wavelength) infers the thin nature of the grown film. This work also re-tracks the controlled etching by reactive ions to achieve large area bi/tri-layer films to fabricate high performance devices. An advanced dual MOS (DMOS) structure on SiO₂/p-Si substrate is fabricated which shows tremendous performance by means of photo-capacitance under illumination condition where photo-carriers can survive the higher probe frequencies. Under illumination conditions, the DMOS device demonstrates superior performance, exhibiting a significantly strong electron-inversion region compared to HfO₂/SiO₂/p-Si and SiO₂/p-Si MOS devices, even at high frequencies (1-10 MHz). This work thus presents a potential approach for capacitance-based, highly sensitive photodetection within conventional Si technology, enabled by integrating WSe₂/W as the active material.

Abstract

Here, we report a full-fledged journey towards the material synthesis and characterization of a few-layered/thin WSe₂ using sputtered W-films on SiO₂/Si substrates followed by electrical studies under dark and illumination conditions. Growth temperature of 500oC and a gas flow rate of 55 sccm are found to be the optimized parameters for the formation of thermodynamically stable WSe₂ with dominant Raman peak at 265 cm⁻¹. XRD and HR-TEM measurements clarify the formation of high crystallinity along the c-axis and quasi-crystallinity along a and b axes, respectively. Lower intensities from Raman-measurement and PL-peak at 768 nm (with 532 nm excitation wavelength) infers the thin nature of the grown film. This work also re-tracks the controlled etching by reactive ions to achieve large area bi/tri-layer films to fabricate high performance devices. An advanced dual MOS (DMOS) structure on SiO₂/p-Si substrate is fabricated which shows tremendous performance by means of photo-capacitance under illumination condition where photo-carriers can survive the higher probe frequencies. Under illumination conditions, the DMOS device demonstrates superior performance, exhibiting a significantly strong electron-inversion region compared to HfO₂/SiO₂/p-Si and SiO₂/p-Si MOS devices, even at high frequencies (1-10 MHz). This work thus presents a potential approach for capacitance-based, highly sensitive photodetection within conventional Si technology, enabled by integrating WSe₂/W as the active material.

Abstract

Here, we report a full-fledged journey towards the material synthesis and characterization of a few-layered/thin WSe₂ using sputtered W-films on SiO₂/Si substrates followed by electrical studies under dark and illumination conditions. Growth temperature of 500oC and a gas flow rate of 55 sccm are found to be the optimized parameters for the formation of thermodynamically stable WSe₂ with dominant Raman peak at 265 cm⁻¹. XRD and HR-TEM measurements clarify the formation of high crystallinity along the c-axis and quasi-crystallinity along a and b axes, respectively. Lower intensities from Raman-measurement and PL-peak at 768 nm (with 532 nm excitation wavelength) infers the thin nature of the grown film. This work also re-tracks the controlled etching by reactive ions to achieve large area bi/tri-layer films to fabricate high performance devices. An advanced dual MOS (DMOS) structure on SiO₂/p-Si substrate is fabricated which shows tremendous performance by means of photo-capacitance under illumination condition where photo-carriers can survive the higher probe frequencies. Under illumination conditions, the DMOS device demonstrates superior performance, exhibiting a significantly strong electron-inversion region compared to HfO₂/SiO₂/p-Si and SiO₂/p-Si MOS devices, even at high frequencies (1-10 MHz). This work thus presents a potential approach for capacitance-based, highly sensitive photodetection within conventional Si technology, enabled by integrating WSe₂/W as the active material.