Influence of RF power on physical properties of ZnO:ZnF2 thin films by RF magnetron sputtering

Abstract

Fluorine-doped zinc oxide (FZO) thin films were prepared on glass substrates at room temperature by radio frequency (RF) magnetron sputtering with a ceramic ZnO target containing 1.5wt% zinc fluoride (ZnF2). This study investigates the influences of RF powers of sputtering and H2 plasma treatment on properties of FZO films. For as-deposited films, all films had a highly (002) preferential c-axis orientation and film crystallinity was improved with increasing deposition power. The film resistivity decreased and the average optical transmittance in the visible range increased with increasing deposition power. The lowest resistivity of 9.29×10−4Ω-cm and the average transmittance above 90% were obtained at the power of 150W. For plasma treated films, the crystal structure had no significant change but the film resistivity further decreased to 7.92×10−4Ω-cm and the optical bandgap increased to 3.725eV. The calculated figures of merit exhibited that the film deposited with a high deposition power and a low H2 plasma power possessed the optimized optoelectronic properties. The H2 plasma treated FZO thin films have potential to be applied as transparent conducting electrodes.