The fabrication of a p–n junction is the most fundamental step in realizing the electronics, therefore it is important to investigate the possible methods of how to integrate artificially designed structures, i.e., growing oxide thin films on semiconductor n-Si. For the device applications, the structure of a p–n junction has shown a promise diode, lasers, light emitting diode and solar cells. Cupric oxide is a p-type semiconductor with bandgap of about 1.2 to 1.9 eV depending on the current density. In this study, CuO/n-Si thin films were prepared by sol-gel method. I–V characteristics from the CuO/n-Si films shown nonlinear I-V curve of p-n junction. Copper oxide is synthesized in two semiconducting phases (cupric oxide (CuO) and cuprous oxide (Cu2O)) and hydroxyl species (Cu(OH)2) in the surface region of CuO/n-Si thin films from chemical bonding states. The junction of copper oxide and n-Si exhibited nonlinear behavior and rectifying I–V characteristics.

Keywords: ITO, p-n junction, p-type semiconductor, Copper oxide, Chemical bonding states, Sol-gel.