Fast response and broadband self-powered photodetectors based on CZTS/SiNW core-shell heterojunctions for health monitoring

In this work, fast response and broadband self-powered photodetectors based on heterojunctions of vertical smooth silicon nanowires (SiNWs) were proposed, which were achieved through spin-coating p-CZTS on top of n-SiNWs adopting a simple two-step method. First, CZTS was uniformly and tightly attached to the sidewalls of SiNWs in the form of nanoparticles. The prepared CZTS/SiNWs core-shell heterojunctions exhibited typical rectification characteristics in dark and excellent light response characteristics in light illumination. Our device could perform self-driven detection under the UV-VIS-NIR light irradiation without an external energy supply. The responsivity and specific detectivity were estimated to be 14 mAW(-1) and 1.5 x 10(11) Jones, which can be improved to 0.35 AW(-1) and 1.2 x 10(13) Jones at -1.5 V bias. In addition, the present device also possesses distinct advantages of a large I-light/I-dark ratio exceeding 4.25 x 10(4), fast response rate with rise/fall times of 1.4/14.2 mu s, and outstanding environmental stability. Finally, a heart rate health monitoring application by CZTS/SiNWs detector was proposed. All these results may pave a way for the real application of the self-driven detector in the field of health monitoring in the future.

Automated summary

This work proposed fast response and broadband self-powered photodetectors based on heterojunctions of vertical smooth silicon nanowires. The devices achieved self-driven detection under UV-VIS-NIR light irradiation without an external energy supply. The CZTS/SiNWs core-shell heterojunctions exhibited excellent light response characteristics and rectification characteristics.