Superior Performances of Self-Driven Near-Infrared Photodetectors Based on the SnTe:Si/Si Heterostructure Boosted by Bulk Photovoltaic Effect

The upsurge of new materials that can be used for near-infrared (NIR) photodetectors operated without cooling is crucial. As a novel material with a small bandgap of approximate to 0.28 eV, the topological crystalline insulator SnTe has attracted considerable attention. Herein, this work demonstrates self-driven NIR photodetectors based on SnTe/Si and SnTe:Si/Si heterostructures. The SnTe/Si heterostructure has a high detectivity D* of 3.3 x 10(12) Jones. By Si doping, the SnTe:Si/Si heterostructure reduces the dark current density and increases the photocurrent by approximate to 1 order of magnitude simultaneously, which improves the detectivity D* by approximate to 2 orders of magnitude up to 1.59 x 10(14) Jones. Further theoretical analysis indicates that the improved device performance may be ascribed to the bulk photovoltaic effect (BPVE), in which doped Si atoms break the inversion symmetry and thus enable the generation of additional photocurrents beyond the heterostructure. In addition, the external quantum efficiency (EQE) measured at room temperature at 850 nm increases by a factor of 7.5 times, from 38.5% to 289%. A high responsivity of 1979 mA W-1 without bias and fast rising time of 8 mu s are also observed. The significantly improved photodetection achieved by the Si doping is of great interest and may provide a novel strategy for superior photodetectors.

Automated summary

This study demonstrates self-driven NIR photodetectors based on SnTe/Si and SnTe:Si/Si heterostructures. Si doping reduces dark current density and increases photocurrent by approximately one order of magnitude, improving the detectivity D* by approximately two orders of magnitude. The improved performance may be attributed to the bulk photovoltaic effect (BPVE) enabled by the doped Si atoms.