Thickness uniformity and optical/structural evaluation of RF sputtered ZnO thin films for solar cell and other device applications

摘要

Spatial uniformity in thickness and other characteristics over the surface of thin films plays a fundamental role in characterization and device fabrication particularly in the solar cells.We report an investigation in the preparation of zinc oxide (ZnO) thin film on sapphire substrate by RF magnetron sputtering and characterization by spectral reflectance,photoluminescence,transmittance,and atomic force microscopy measurements.Surface of the film is spatially analyzed and a comparison is established with the previously reported results of metal organic chemical vapor deposition (MOCVD) grown ZnO film.Results show that ZnO films prepared by sputtering technique are superior in thickness uniformity for practical applications.Optical quality of the films prepared by sputtering is similar or even shows better quality compared to the films grown by MOCVD.Furthermore,the importance of film thickness uniformity in particular with reference to the solar cell performance is discussed that,so far,could not draw adequate attention from the research community.