The electro-optic and photonic properties of TU:ZnO thin-film-based photodiodes prepared by sol–gel spin coating

Abstract In this paper, we report the characteristics of undoped and Thiourea (TU)-doped ZnO thin films deposited on glass and p-Si substrates via sol–gel spin coating technique. The energy dispersive X-ray (EDX) spectra verify the atomic percentage of Zn, O, and S in ZnO at various TU (an organosulfur compound) concentrations. The surface roughness parameters of ZnO composed of nanofibers show improvement depending on TU doping. The structural properties of ZnO films with (002) and (101) preferential orientations are evaluated systemically as the hexagonal wurtzite from XRD analyses. The energy gap ( E g ) value of the TU-doped ZnO thin films is found to be 3.25–3.27 eV from optical measurements. TU-doped ZnO/p-Si heterojunction shows the TU wt% content-nonsensitive rectification property, giving a ratio of 10 3 . The open-circuit ( V oc ) value of 0.5% TU-doped ZnO/p-Si heterojunction device is found to be 291 mV, decreasing with increasing TU ratio. The results show that the optimum doping or properly adjusting for ZnO is promising for the future of photovoltaic technology and display applications.