Solar-Blind UV Photodetector Based on Atomic Layer-Deposited Cu2O and Nanomembrane β-Ga2O3 pn Oxide Heterojunction

Herein, we present a solar-blind ultraviolet photodetector realized using atomic layer-deposited p-type cuprous oxide (Cu 2 O) underneath a mechanically exfoliated n-type β-gallium oxide (β-Ga 2 O 3 ) nanomembrane. The atomic layer deposition process of the Cu 2 O film applies bis( N , N '-di-secbutylacetamidinato)dicopper(I) [Cu( 5 Bu-Me-amd)] 2 as a novel Cu precursor and water vapor as an oxidant. The exfoliated β-Ga 2 O 3 nanomembrane was transferred to the top of the Cu 2 O layer surface to realize a unique oxide pn heterojunction, which is not easy to realize by conventional oxide epitaxy techniques. The current-voltage ( I - V ) characteristics of the fabricated pn heterojunction diode show the typical rectifying behavior. The fabricated Cu 2 O/β-Ga 2 O 3 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.