Ultralow Dark Current and High On/Off Ratio Photodetector Based on a Two-Dimensional GeSe/VP Heterostructure

The potential of two-dimensional heterostructures is promising for the advancement of future electronics and optoelectronics multifunction devices due to their tunable band structure, optical sensitivity, and highly controllable electronic transport behaviors. In this study, we achieved success in creating a photodetector based on a vertically stacked GeSe/violet phosphorus (GeSe/VP) van der Waals heterostructure. The GeSe/VP heterostructure shows a clear gate-tunable rectification behavior, which is attributed to the barrier formed between GeSe and VP. The photodetector based on the GeSe/VP heterostructure shows an ultralow dark current (100 fA) and excellent photoelectric performances with a high on/off ratio (×10 3 ), a fast response time of 166 ms, and a high light responsivity of 5 mA/W for visible light of 435 nm under zero-bias. These results demonstrate that the two-dimensional VP-based heterostructure is expected to develop advanced high-performance photodetectors for nanooptoelectronics in the future.