GaN/CuI heterostructure ultraviolet photovoltaic detector for low-power optical communication

In this work, a planar structured GaN/CuI heterojunction ultraviolet photodetector (UVPD) with a self-powered manner was constructed by the spin-coating method. Both UVA and UVC waveband lights were precisely detected by this designed GaN/CuI PD. Irradiated upon 365 nm UVA light, our PD device performed decent self-powered photoresponse properties with a photo-to-dark current ratio (PDCR) of 1.3 × 10³, a responsivity of 228 mA/W, and a specific detectivity of 4.3 × 10¹³ Jones at zero bias. There was barely degeneration in photocurrent during continuous reliability testing, even with the device being placed in air for five months without package. Severed as an optical signal receiver, the GaN/CuI heterojunction UVPD decoded a binary message of "GOOD" in a homemade optical communication system. These results indicated a great potential application of the self-powered GaN/CuI UVPD in energy conservation wireless communications.