Design of self-driven position-sensitive detector based on PtTe2/n-Si heterojunction

Position-Sensitive Detector (PSD) is a photodetector that can detect the position of an incident spot, which plays a critical role in motion tracking. PtTe₂ has a tilted Dirac cone with linear dispersion, which makes it a promising candidate for studying novel quantum phenomena and optoelectronics. Herein, a tellurium-vapor transformation approach is utilized for wafer-scale PtTe₂ preparation, and a new and low-cost PSD is fabricated by constructing PtTe₂/n-Si heterojunction. The PtTe₂/n-Si PSD exhibits a small nonlinearity of only 3.9%, indicating good linearity with zero bias and the work area reaches 3 mm by 3 mm. Furthermore, the response speed is less than the millisecond level. Theoretical analysis indicates that the barriers at PtTe₂/n-Si interface and ultra-high conductivity of PtTe₂ cause the lateral spread of photo-carriers. This work demonstrates a universal strategy for low-cost photodetector towards the PSD applications.