Wide Bandgap Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering at Room Temperature

Abstract

Room temperature RF magnetron sputtering deposition of Zinc Oxide thin films on a glass substrate was carried out by varying deposition parameters such as sputtering pressure, target-to-substrate distance, and RF power. The as-deposited film at 75 W, sputtering pressure of 9.8 mbar and a target-to-substrate distance of 104 mm has showed a band gap of 3.31 eV and RMS surface roughness of 7.1 nm. Electrical characterization and UV–VIS results reveal its high resistivity (1.3 × 107 Ω-cm) and transparency >86% in a wide optical range (494–1100 nm). This film could be used as a buffer layer of CIS solar cells, SAW, and other similar thin film devices over a flexible substrate.