CZTS based novel bifunctional photovoltaic and self-powered photodetection nano system

Abstract CZTS (Cu 2 ZnSnS 4 ) is a quaternary semiconductor that is environmentally friendly, less expensive. In this paper, we report on the optimization and fabrication of CZTS-based heterojunction nanodevices for bifunctional applications such as solar cells and photodetectors. CZTS thin films were deposited on top of (Molybdenum) Mo-coated glass substrates via RF sputtering at 100 and 200 W. Rapid thermal processing (RTP) was used at 300, 400, and 500 °C temperatures. CdS (cadmium sulphide) was deposited on CZTS using a chemical bath deposition system with 3- and 5-min deposition times. ZnO (zinc oxide) and AZO (aluminium doped zinc oxide) layers were deposited using RF (radio frequency) sputtering to create the solar device. XRD confirms the formation of a tetragonal structure with increased crystallinity due to the use of RTP. Raman reveals the characteristic Raman shift peak associated with CZTS at 336 and 335 cm −1 . The FESEM shows a relationship with RTP temperature. Surface features, including grain size, vary with RTP temperature. The ideality factor is nearly 2, indicating imperfection in the Mo/CZTS interface. Schottky barrier height estimates range from 0.6 to 0.7 eV. Absorbance and transmittance show a predictable fluctuation with RTP temperature. Photovoltaic device was built using the higher crystalline feature of CZTS in conjunction with CdS deposited at 3 and 5 min. The efficiency of CdS deposited after 3 and 5 min was 1.15 and 0.97 percent, respectively. Fabricated devices were used for wavelength-dependent photodetection. This work demonstrated self-powered photodetection.