Production and characterization of ZnO/Cu2O based devices growing with spin coating method

Using spin coating method, which is rather easy to apply, n-ZnO window layer first coated on ITO coated glass by using abundant and economical materials such as copper and zinc. Then the p-Cu2O photoactive layer was coated on the obtained structure to form p-n joint structure. The fabricated n-ZnO / p-Cu2O junction was characterized device with Ag / ITO / ZnO / Cu2O / Ag structure. The morphological, structural, optical, and electrical characteristics of n-ZnO / p-Cu2O heterojunction were examined by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and ultraviolet-visible spectroscopy (UV-VIS). The FE-SEM cross-section images approve the formation of well-defined cubic Cu2O grains on flat surface of ZnO layer. XRD results showed that the sharpness of the peaks is a sign of high crystallinity. Current–voltage (I–V) characteristic of n-ZnO/p-CuO heterojunctions has been investigated, I–V curve shows a distinct diode-like rectifying behavior. It was observed that as the molarity increased, the crystallinity increased, homogeneity partially disappeared and cracks appeared on the material. The effect of the solution molarity, film thickness, drying temperature and annealing atmosphere on the film quality has been investigated.