Fabrication of MgZnO films by molecular precursor method and their application to UV-transparent electrodes

MgZnO thin films were fabricated by the molecular precursor method (MPM) for the realization of cost-effective near-ultraviolet (UV) transparent electrodes for GaN-based UV light-emitting diodes (LEDs). The fabrication by MPM requires a common solution. It was clarified that ammonia aqueous is a common solvent for Mg, Zn and Ga precursors. MgZnO thin film was successfully fabricated on a quartz glass substrate using MgZnO precursor solution. The solid phase composition of Mg in the film is 40-50% of its molar fraction in the liquid phase. The X-ray diffraction patterns indicate the films have a hexagonal single phase, the same as in the case of ZnO. Ga doping of the MgZnO films enables their resistivity control. The possibility of applying MgZnO films for UV transparent electrodes on GaN-based UV LEDs is discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)