Tunable Bandgap of LuxIn1-xO Ternary Alloy for Solar-Blind Ultraviolet Detection

In this study, Lu atoms are incorporated into In2O3 lattice by magnetron co-sputtering, expanding the bandgap of LuxIn1-xO (
$0 < $
x < 1) to the solar-blind ultraviolet (SBUV) region. Based on the Lu0.39In0.61O film with a bandgap of 5.2 eV, a Pt/Lu0.39In0.61O/GaN device with stable and reliable detection performance to SBUV is fabricated. Under 0 V bias, the detector shows a maximum photoresponsivity of 0.81 mA/W under 255 nm irradiation, an SBUV-visible rejection ratio (R255 nm/R400 nm) of 318, and a decay time of 0.56 s. Compared with Au/Lu0.39In0.61O/GaN device, this detector has a larger short-circuit current, a higher open-circuit voltage, and a lower dark current density. The Schottky junction between the Lu0.39In0.61O film and the Pt electrode is regarded as a key factor for the reliable optoelectronic performance exhibited by the device at 0 V bias. This work is significant in extending the application of LuxIn1-xO ternary alloy in SBUV detection.