InGaN p–i–n ultraviolet-A band-pass photodetectors

InGaN p–i–n ultraviolet (UV)-A band-pass photodetectors (PDs) with indium-tin-oxide (ITO) contact and with flip-chip (FC) technology were both fabricated and characterised. With −5 V applied bias, it was found that measured dark currents were 7×10−10 and 4×10−10 A for FC p–i–n PDs with i-In0.1Ga0.9N and i-In0.05Ga0.95N active layers, respectively. With an incident light wavelength of 385 nm, it was found that external quantum efficiencies of FC p–i–n PD and ITO p–i–n PD were around 67 and 35%, respectively. The rejection ratios of FC p–i–n PD were also found to be larger than those observed from ITO p–i–n PD.