Cubic MgZnO thin films on sapphire substrate: effect of deposition temperature

The structural, morphological and optical properties of cubic MgZnO thin films deposited on sapphire substrates by radio frequency (RF) magnetron sputtering method at different deposition temperatures (RT, 500 degrees C and 800 degrees C) were investigated. The presence of Mg in deposited samples was confirmed through SIMS depth profile. Moreover, Mg content of the alloys was calculated using a quadratic approximation depending on band gap bowing parameter. The film deposited at 500 degrees C with band gap energy of 5.0eV has better crystallinity and atomic homogeneity than the others. Both film quality and Mg atomic distribution deteriorated at 800 degrees C due to thermal effect on the substrate surface. The results explore the applicability of RF-sputtered cubic MgZnO thin films as an active sensor area for deep UV-based optoelectronic applications.