Solar-Blind UV Photodetector Based on Atomic Layer-Deposited CuO and Nanomembrane β-GaO Pn Oxide Heterojunction

Herein, we present a solar-blind ultraviolet photodetector realized using atomic layer-deposited p-type cuprous oxide (CuO) underneath a mechanically exfoliated n-type β-gallium oxide (β-GaO) nanomembrane. The atomic layer deposition process of the CuO film applies bis(,'-di-secbutylacetamidinato)dicopper(I) [Cu(Bu-Me-amd)] as a novel Cu precursor and water vapor as an oxidant. The exfoliated β-GaO nanomembrane was transferred to the top of the CuO layer surface to realize a unique oxide pn heterojunction, which is not easy to realize by conventional oxide epitaxy techniques. The current-voltage (-) characteristics of the fabricated pn heterojunction diode show the typical rectifying behavior. The fabricated CuO/β-GaO photodetector achieves sensitive detection of current at the picoampere scale in the reverse mode. This work provides a new approach to integrate all oxide heterojunctions using membrane transfer and bonding techniques, which goes beyond the limitation of conventional heteroepitaxy.