Photoluminescence Characterization of ZnO Thin Films Grown by RF- Sputtering

Abstract

This article presents photoluminescence (PL) characterization of ZnO thin films deposited by radio‐frequency magnetron sputtering method on sapphire and n‐type Si (100) substrates. PL measurements were carried out at room temperature to investigate the energy band gaps and optical quality of the ZnO thin films. In order to draw a specific picture of surface morphology of ZnO thin films, atomic force microscope images were taken. All the results were compared to the results obtained from the bulk ZnO sample. The results revealed that the energy band gap of ZnO thin films grown on n‐type Si (100) is higher than ZnO on sapphire. However, energy band gap of bulk ZnO is higher compared to both ZnO on n‐type Si (100) and sapphire (Al2O3). This is probably due to the crystalline quality because good crystallinity increases the radiation recombination and hence increase the intensity of the NBE emission.