Ultraviolet radiation-induced photovoltaic action in γ-CuI/β-Ga2O3 heterojunction

We report on the fabrication of gamma-phase copper iodide (gamma-Cul) and beta-gallium oxide (beta-Ga2O3) heterostructure device and obtaining the ultraviolet (UV) radiation responsive photovoltaic action. The crystalline gamma-Cul with predominant (1 1 1) plane orientation was deposited on the beta-Ga2O3 by thermal evaporation process under vacuum condition. The electrical analysis revealed that the gamma-Cul/gamma-Ga2O3 heterojunction possess an excellent rectifying diode characteristic with high rectification ratio and turn-on voltage. The fabricated heterojunction device showed a photovoltaic action under solar-blind UV irradiation (254 nm) with outstanding photovoltage of 0.706 V and photocurrent of 2.49 mA/W. The device also showed a photovoltaic action under illumination of 365 nm and 300-400 nm wavelength of UV light, corresponding to absorption due to the gamma-Cul layer. The UV irradiation-induced photovoltaic action in the gamma-Cul/beta-Ga2O3 with outstanding photovoltage and excellent diode characteristics can be significant for self-powered UV photodetector applications. (C) 2019 Elsevier B.V. All rights reserved.