Transparent p/n diode device from a single zinc nitride sputtering target

Zinc oxide (ZnO) thin films showing bipolar conductivity were fabricated by sputtering of zinc nitride target in plasma containing mixture of Ar-O₂ gasses. Sputtering in pure Ar plasma produced conductive and opaque zinc nitride (ZnN) films while upon introduction of oxygen up to 30% into the plasma highly transparent single phase polycrystalline n-type ZnO films have been grown. ZnN sputtering in Ar plasma containing more than 30% oxygen produced p-type ZnO films. Hall-effect and photoluminescence measurements revealed the presence of zinc vacancies and nitrogen which are acting as acceptor dopants in p-type ZnO. A heterostructure was fabricated in a single deposition run consisting of n-ZnN and p-ZnO which exhibited rectifying behavior with 2-2.5 V turn-on voltage. Improvements on the formed p/n heterostructure as well as the potential of using single sputtering target in fabrication of Zn-based homo- and hetero-junctions are discussed.