All-Oxide Ga$_{\mathrm{2}}$O$_{\mathrm{3}}$-NiO$_{\mathrm{x}}$ PN Junction Diodes Enabled by Tunable Electrical and Optical Properties of Nickel Oxide (NiO$_{\mathrm{x}})$ and Gallium Oxide (Ga$_{\mathrm{2}}$O$_{\mathrm{3}})$ Thin Films Deposited by Pulsed Laser Deposition at Room Temperature

The need of stable, high quality electronic devices such as pn junctions, light-emitting diodes, transistors and UV photodetectors has pushed the development of both, p- and n-type, transparent semiconductor oxides. Thin films heterojunctions have been reported using ZnO and IGZO as n-type and NiO as p-type, with at least one metallic contact. Pulsed laser deposition (PLD) offers advantages over other deposition methods as more homogeneous, smoother surfaces with high reproducibility. In this work we present a new all-oxide heterojunction based in oxides deposited by PLD at room temperature without heat treatment. This heterojunction has low leakage current, an ideality factor close to 2,10$^{\mathrm{5}}$ on/off ratio and acceptable on-voltage, with a wide band gap which makes it even more interesting for optoelectronics applications. Temperature dependence on the device performance is also discussed.