The effect of annealing temperature on the optical and electrical properties of cubic MgZnO films grown by RF magnetron sputtering

A series of cubic MgZnO films with a band gap of 5.0 eV (240 nm) are grown on the Si substrate by radio-frequency (rf) magnetron sputtering with various annealing temperature. Highly (111) textured single phase cubic MgZnO films with enhancement of conductivities are received through thermal annealing. The effects of annealing temperature on the structural, optical and electrical properties of cubic MgZnO films have been investigated. With increasing annealing temperature, phase separation of MgZnO films has been suppressed due to the internal strain is partially relieved by the thermal annealing. In addition, the resistivity (electron mobility, carrier concentration) decrease (increase) with an increase of annealing temperature which implies that high temperature annealing could improve the crystal quality and thereby reduce the grain boundary scattering for electron transport. Our results represent a meaningful step toward fabrication of high quality cubic MgZnO thin films use in UVC region.