Raman spectroscopic study on NiO thin film

Abstract

Polycrystalline NiO thin films were prepared on the Pt substrate by the DC reactive sputtering in different oxygen content circumstances. And then Raman measurements were performed at room temperature. In the Raman spectrum of the samples two increased main peaks of the Raman intensity were observed by the linear increase of oxygen content. One is located around 540cm-1 and another is around 1500cm-1 broadly. Among these two features we concentrated on the Raman feature around 540cm-1. After the Raman data was normalized, in the range from 300cm-1 to 700cm-1 three main peaks were observed. After we assigned these peaks to characteris tic phonon modes in the polycrystalline NiO thin film, we could conclude that because of the structural effects the polycrystalline NiO thin films have a lower defect induced TO phonon energy than the crystal NiO but they have a similar optical property with the Alcalihalide group as ever.