Development of ZnO/Ta₂O₅ heterojunction using low-temperature technological processes

Abstract

ZnO/Ta 2 O 5 heterojunctions were formed on glass substrates using low temperature processes. Formerly insulating Ta 2 O 5 films were deposited on glass substrates by vacuum evaporation using Ta 2 O 5 powder, Afterwards transparent and conductive ZnO films were formed on the Ta 2 O 5 films by thermal oxidation at 320 0 C in air atmosphere of zinc (Zn) films deposited by dc sputtering process. Structural and optical properties of ZnO were investigated by X-ray diffraction (XRD) and photoluminescence (PL). The Ta 2 O 5 insulating films were characterized by Raman scattering. The ZnO/Ta 2 O 5 heterojunction was characterized by current-voltage measurements at room temperature as well as transient response under a rectangular-pulse voltage source. The electrical and the transient response suggest that the ZnO/Ta 2 O 5 heterojunction is a potential alternative for the fabrication of alternating-current-driven thin film electroluminescent (ACTFEL) devices.