Effects of Oxygen Flux on the Aluminum Doped Zinc Oxide Thin Films By Direct Current Magnetron Sputtering

Abstract

Abstract Aluminum doped zinc oxide (AZO) thin films were prepared by direct current (DC) magnetron sputtering with pure argon gas on glass substrates, usually showed relatively low transmission in our experiments. It was unfavorable for AZO as front electrode for silicon thin film solar cells. In order to increase the transmission of AZO thin films, we tried to add oxygen gas into vacuum chamber during sputtering processes. The microstructures, optical and electrical properties of AZO films were investigated. During the process of sputtering, the O2 flow rate indicated a greater negative impact on the electrical properties of AZO thin films than the improvement of optical properties. Raman peak related to zinc interstitial atoms (560cm-1) was observed in the AZO thin films grown with different O2 flow rates. With the increasing of O2 flow rate, intensity of Raman peak at 560cm-1 decreased. When the O2 flow rate increased, more O atoms involved in the process of reactive sputtering, and O and Zn interstitial atoms combined to Zn-O bond, which reduced the Zn interstitial atoms. The transmission between 400 nm and 1100 nm was enhanced by the increase of O2 flow rate. The average transmissions of AZO thin films were more than 90% in the visible and near-infrared range and the resistivity of these films increased acutely.