SnS_2/Si nanowire vertical heterostructure for high performance ultra-low power broadband photodetector with excellent detectivity

摘要

Nanoparticle-nanowire heterostructures provide a new platform for photodetection applications owing to their higher light absorption, large responsivity, and excellent separation efficiency of photogenerated electron-hole pairs. Herein, we report a SnS_2/Si nanowire heterostructure photodetector with excellent optoelectronic properties. A high-quality SnS_2/Si nanowire heterostructure was prepared by simply spin coating a wet chemically synthesized SnS_2 on a vertically standing Si nanowire made by metal assisted chemical etching. The as-prepared SnS_2/Si nanowire heterostructure exhibits a robust p-n junction with excellent photodetector characteristics. The photodetector based on the heterostructure shows a photo-responsivity of ～3.8 AW~(-1), a specific detectivity up to ～ 2 × 10~(14) Jones, and an on/off ratio up to ～ 10~2 at 340 nm illumination wavelength with a significantly low optical power density of 53.75 nW/mm~2 at zero bias (0 V). The photo-responsivity reached its maximum value of ～10~2A/W and detectivity of ～1 × 10~(14) Jones at the same wavelength with an applied bias of -2 V. In addition, the heterostructure photodetector provides significantly good photodetector key parameters (responsivity ～5.3 A/W, detectivity ～ 7.5 × 10~(12) Jones, rise/decay time ～0.4/0.4 s) at -2 V bias over a wide spectral range from 400 to 1100 nm. The Si nanowire and SnS_2 nanoparticle heterostructure devices with an enhanced junction area open up an exciting field for novel non-toxic and environmental friendly broadband optical detection applications and optoelectronic memory devices with high responsivity, ultrahigh sensitivity, and self-sufficient functionality at low power consumption and low cost with ease of processing.