Effect of a hydrogen ratio in electrical and optical properties of hydrogenated Al-doped ZnO films

Abstract

This study examined the effect of the hydrogen ratio on the electrical and optical properties of hydrogenated Al-doped zinc oxide (AZO) thin films deposited by rf magnetron sputtering using a ceramic target (98 wt% ZnO, 2 wt% Al2O3). Various AZO films on glass were prepared by changing the H-2/(Ar + H-2) ratio at room temperature. The AZO/H films showed a lower resistivity and a higher carrier concentration and mobility than the AZO films. However, the resistivity and mobility of the AZO/H films increased and decreased with increasing H-2 flow ratio, respectively. As a result, the AZO/H films grown with 2% H-2 addition showed excellent electrical properties with a resistivity of 4.98 x 10(4) Omega cm. The UV-measurements showed that the optical transmission of the AZO/H films was > 85% in the visible range with a wide optical band gap. In addition, the effect of H-2 flow ratio on the structure and composition of hydrogenated AZO thin films have also been studied.