Affiliation:
1. College of Physical Science and Technology, Semiconductor Photonics Research Center, Xiamen University , Xiamen 361005, China
Abstract
Broadband high-performance photodetector operating at ultraviolet (UV) to infrared (IR) wavelengths is critical for numerous applications ranging from environmental sensing, medical diagnostics, to high-resolution spectroscopy. In this Letter, a p-GaSe/n-Si van der Waals heterojunction phototransistor (HPT) with a Schottky barrier (SB) collector on silicon-on-insulator is proposed and demonstrated to secure sensitive detection at UV (270 nm) to near-IR (1500 nm) wavelengths. Remarkable responsivities of 114 A/W at 275 nm and 1.3 A/W at 1550 nm as well as large specific detectivities of >1011 Jones at 275 nm and 1.1 × 109 Jones at 1500 nm are achieved. The absorption of UV and visible light mainly occurs in GaSe emitter and Si base. While the construction of Pt/n-Si SB enables extended IR response (>1107 nm) by the internal photoemission effect (IPE) and effectively suppresses the dark current of the HPT to a low value of 0.5 nA at a bias of 5 V simultaneously. The huge hole/electron injection ratio resulted from the large energy bandgap offset between GaSe and Si significantly amplifies the photocurrent. In combination with the resonant cavity modulation effect, a high photocurrent gain is produced in the HPT. These results demonstrate that the two-terminal mixed-dimensional p-GaSe/n-Si HPT with a SB collector is a promising candidate for extending the response wavelength to both UV and NIR bands.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
XMU Undergraduate Innovation and Entrepreneurship Training Programs
Subject
Physics and Astronomy (miscellaneous)