Light intensity-dependent performance analysis of self-powered CZTS (Cu2ZnSnS4)/n-Si heterojunction photodetector with wavelength-sensitive interface

This study investigates the broadband photodetector performance of a CZTS/n-Si heterojunction. CZTS thin films were characterized using XRD, Raman, UV-Vis, SEM, and EDS. To create a high-performance, broadband p-n heterojunction, n-type silicon was strategically selected to complement the intrinsic p-type nature of CZTS, thereby enhancing the separation and collection of photo-generated carriers. The device demonstrated outstanding photoresponsivity across white, yellow, UV (365 and 395 nm), and IR (850 nm) spectrums. Under white light (150 mW/cm2), the device achieved an on/off ratio of 3.46 x 104, a detectivity of 2.71 x 10 1 1 Jones at zero bias, and a responsivity of 129 mA/W at-2.0 V. Peak performance was observed at 590 nm, yielding a high responsivity of 1069 mA/W (-2.0 V) and a detectivity of 2.49 x 10 1 2 Jones (zero bias). Furthermore, the device exhibited excellent environmental stability over 80 days and rapid response times (rise/fall: 11.7/15.8 ms). These results highlight the CZTS/n-Si heterojunction as a promising candidate for high-performance, stable, next-generation optoelectronic applications."