2009 Volume 7 Pages 294-297
The effects of the PLD bias voltage technique on the ZnO film quality have been investigated. The ZnO films were grown on sapphire substrates under bias voltages and oxygen atmosphere conditions. A molybdenum mesh electrode is set between the substrate and the target. The bias voltages and the oxygen pressures were changed between ±500 V and between 10-2 and 10-6 Torr, respectively. Photoluminescence measurement showed that the defect density had minimum values when the bias voltage was about +200V and the oxygen pressure was 10-2 Torr. The optimum bias voltages decrease from +400 to +200 V by using oxygen atmospheres. Because the defect densities are decreased significantly by applying bias voltages under the optimized oxygen condition, the reasons of the improved ZnO film quality comes from not only the compensation of the decrease in the oxygen ratio in the film but also the decrease of the film damages caused by the high energy particles in the plume. [DOI: 10.1380/ejssnt.2009.294]
