High-speed, low-bias operated, broadband (Vis-NIR) photodetector based on sputtered Cu2ZnSn(S, Se)4 (CZTSSe) thin films

Photodetectors have large applications in the current ongoing pandemic. These can be used to study the growth of viruses where depending upon the concentration the light intensity will be reduced. Since the viruses grow very fast therefore a device with very low response time as well as quick recovery will be useful for this study. If the device can be made from the non-toxic materials and sizes are quite small, they can be used for in vitro studies as well. Kesterite Cu2ZnSn(S, Se)4 (CZTSSe) thin film can be deposited over flexible substrates. The detectivity of even very small area device is very high with ultra-small response and recovery time. The CZTSSe PD exhibited excellent broadband (Vis-NIR) photoresponse, high responsivity of 18.0 mA.W−1, a fast rise time of 82 ms, and a decay time of 97 ms, as well as high detectivity (∼109 Jones) with favorable self-powered characteristics. This work suggests significant scientific insights for photoconductivity properties of emerging kesterite CZTSSe thin-film materials for broadband, low-cost, high-efficiency next-generation thin-film photodetectors for various optoelectronic applications including diagnostic.