Gate-Controlled NiO/Graphene/4H-SiC Double Schottky Barrier Heterojunction Based on a Metal-Oxide-Semiconductor Structure for Dual-Mode and Wide Range Ultraviolet Detection

Abstract

Based on a metal-oxide-semiconductor (MOS) structure, a double Schottky barrier junction (SBJ) made of NiO/graphene/4H-SiC is built and employed in ultraviolet (UV) detection. The hole concentration of NiO can be modulated as depleted or accumulated states with gate voltages, which allows the device to work in dual-mode when used as a photodetector. In this work, a negative gate bias causes the device to operate as a photoconductive detector with gain due to the negligible Schottky barrier, whereas a zero or positive gate bias makes it work as a Schottky photodiode. The device has a high responsivity of 103.3 A/W and a gain of 490.8 despite the low light intensity (261 nm laser @ 30.19 μW/cm 2 ) at V DS = 5 V and V GS = −3 V. The NiO layer and SiC substrate both serve as UV absorption materials and produce photogenerated carriers, and the device has a wide UV response range from 240 to 400 nm with a gain of 80.34 when V DS = −3 V and V GS = 0 V at 240 nm. The above findings suggest that this MOS-based NiO/graphene/4H-SiC double SBJ has a great prospect in practical UV detection.

Ultrafast self-powered CsPbCl3ultraviolet photodetectors with choline chloride for surface passivation and charge transport regulation

“…UV photodetection is attracting increasing attention owing to its significant applications in advanced communications, fire detection, military warning, chemical/biological sensing, etc. [1][2][3] Various conventional wide bandgap semiconductors, such as GaN, 4,5 Ga 2 O 3 , 6 and SiC, 7 have been explored for the fabrication of UV photodetectors. However, the unsatisfactory photoelectric properties as well as the expensive and complex manufacturing processes of the semiconductors themselves hinder the performance improvement and widespread applications of these devices.…”