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 (Cu2O) underneath a mechanically exfoliated n-type β-gallium oxide (β-Ga2O3) nanomembrane. The atomic layer deposition process of the Cu2O film applies bis(N,N′-di-secbutylacetamidinato)dicopper(I) [Cu(5Bu-Me-amd)]2 as a novel Cu precursor and water vapor as an oxidant. The exfoliated β-Ga2O3 nanomembrane was transferred to the top of the Cu2O 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 Cu2O/β-Ga2O3 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 heteroe...