Poly-Si/a-Si/4H-SiC p-n heterojunction broadband photodetector prepared by magnetron sputtering

With the increasing complexity of scenarios, there is a growing need for broadband photodetectors (PDs). In this work, we report a polycrystalline-Si (poly-Si)/amorphous-Si (a-Si)/4H-SiC p-n heterojunction PD with efficient response in a broad spectral range of ultraviolet-visible-near-infrared. The poly-Si/a-Si/4H-SiC heterojunction was achieved by magnetron sputtering and annealing. The fabricated heterojunction device has a low dark current of 1 pA at -40 V and a fast response time of 3 ns due to the outstanding rectification characteristics of the heterojunction combined with narrow bandgap and wide bandgap material. In addition, the carrier behavior of the heterojunction exposed to broadband light is analyzed in detail by constructing the energy band diagram.