Photodiode Based on CdO Thin Films as Electron Transport Layer

Abstract

Cadmium oxide (CdO) thin films were synthesized by the sol–gel method. The films were analyzed by means of XRD, AFM, and UV/Vis spectrophotometry. X-ray diffraction patterns confirm that the films are formed from CdO with cubic crystal structure and consist of nano-particles. The energy gap of the prepared film was found to be 2.29 eV. The current–voltage (I–V) characteristics of the CdO/p-Si heterojunction were examined in the dark and under different illumination intensities. The heterojunction showed high rectifying behavior and a strong photoresponse. Main electrical parameters of the photodiode such as series and shunt resistances (Rs and Rsh), saturation current I0, and photocurrent Iph, were extracted considering a single diode equivalent circuit of a photovoltaic cell. Results indicate that the application of CdO thin films as an electron transport layer on p-Si acts as a photodetector in the field of the UV/visible. © 2016, The Minerals, Metals & Materials Society.