Effect of Al, Ga, and In Doping on the Optical, Structural, and Electric Properties of ZnO Thin Films

ZnO thin films with oxygen vacancies and doped with Al, Ga, and In (Zn1-xMxO1−y (x = 0.03)) have been successfully deposited on soda-lime glass substrates using a simple soft chemical method. The crystalline structure shows a single hexagonal phase of wurtzite with preferred crystal growth along the 002 plane. The surface morphology, characterized by SEM, revealed that the grain shape varies depending on the dopant agent used. Optical measurements displayed an increase in the bandgap values for doped films from 3.29 for ZnO to 3.35, 3.32, and 3.36 for Al, Ga, and In doped films, respectively, and an average transmittance superior to 90% in some cases (in the range between 400 and 800 nm). The electrical response of the films was evaluated with a four-point probe being 229.69, 385.71, and 146.94 Ω/sq for aluminium, gallium, and indium doped films, respectively.We also appreciate the characterization assistance of the Central Service of Scientific Instrumentation (SCIC) at the University Jaume I. We also thank the group of F. Fabregat (INAM-UJI) for the analysis and characterization assistance.This research was funded by Spanish Ministry of Economy and Competitiveness under the program Programa Estatal de I+D+I orientada a los retos de la sociedad (IGNITE Project Ref. ENE2017-87671-C3-3-R) and program Proyectos de I+D+i» de los Programas Estatales de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i y de I+D+i Orientada a los Retos de la Sociedad, en el marco del Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020 (Ref. PID2020-116719RB-C43)