Electrochemical Deposition of Transparent p-type Semiconductor NiO

Abstract

NiO is a p-type semiconductor having a large band gap (> 3 eV). In this study, thin films containing Ni-O were deposited by the cathodic electrochemical deposition method, and characteristics change by heat treatment was investigated. An aqueous solution containing Ni(NO₃)₂ was used as a deposition solution. X-ray photoelectron spectroscopy showed that the sample before annealing was predominantly Ni(OH)₂. After heat treatment in air at temperatures higher than 300ºC, the NiO phase was observed by X-ray diffraction, and the p-type response was confirmed by the photoelectrochemical measurement. The band gap obtained from the light transmittance measurement was around 3.5eV.