Electrochemical Deposition of Transparent p‐Type Semiconductor NiO

Abstract

SUMMARY 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 300 °C, 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 3.5 eV.