Enhanced performance of a n-Si/p-GaTe heterojunction through interfacial passivation and thermal oxidation

Two-dimensional/three-dimensional heterojunctions are widely fabricated for high-performance photodetectors and various strategies have been developed to optimize their performance. Here, we report a hybrid approach to improve the responsivity and response time of a n-Si/p-GaTe heterojunction simultaneously through interface passivation and thermal oxidation. The responsivity of the n-Si/p-GaTe heterojunction has been increased from 2.2 A W 1 to 4.5 A W 1 at zero bias, and the response/recovery time has been decreased from 22/15 s to 2/5 s at the same time. The AlO x passivation layer reduces the interfacial recombination allowing more carriers to participate in electric conduction and the thermal oxidation shifts the Fermi level of GaTe towards the valence band which enlarges the built-in electric field and accelerates the separation of carriers. This work provides a feasible way to achieve the overall improvement of photodetectors. We report a hybrid strategy to improve the responsivity and reduce the response time of a n-Si/p-GaTe heterojunction simultaneously through AlO x interface passivation and thermal oxidation.