SnS2/Si nanowire vertical heterostructure for high performance ultra-low power broadband photodetector with excellent detectivity

Abstract

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 SnS2/Si nanowire heterostructure photodetector with excellent optoelectronic properties. A high-quality SnS2/Si nanowire heterostructure was prepared by simply spin coating a wet chemically synthesized SnS2 on a vertically standing Si nanowire made by metal assisted chemical etching. The as-prepared SnS2/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 A W−1, a specific detectivity up to ∼ 2 × 1014 Jones, and an on/off ratio up to ∼ 102 at 340 nm illumination wavelength with a significantly low optical power density of 53.75 nW/mm2 at zero bias (0 V). The photo-responsivity reached its maximum value of ∼102 A/W and detectivity of ∼1 × 1014 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 × 1012 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 SnS2 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.