Influence of sputtering pressure on band gap of Zn_(1-x)Mg_xO thin films prepared by radio frequency magnetron sputtering

摘要

Zn_(1-x)Mg_xO thin films were deposited onto quartz glass substrates using a radio frequency magnetron sputtering at various deposition pressures. It was found that the Mg concentration in the Zn_(1-x)Mg_xO thin films significantly increased by decreasing the deposition pressure from 9 to 1 Pa, which contributed to an increase in the band gap of the ZnMgO films. In addition, the Zn_(1-x)Mg_xO thin films, which had a hexagonal wurtzite structure when obtained by high pressure deposition (7 and 9 Pa) at x ≤ 0.478, had a cubic rock-salt crystal structure when deposition pressure was decreased to 1-5 Pa at x ≥ 0.482. These results show that the band gap of the ZnMgO thin films could be easily modulated only by adjusting of the deposition pressure during the radio frequency sputtering process.