Interfacial defect engineering to boost deep-ultraviolet photodetection based on a wide-bandgap semiconductor heterostructure†

Abstract

Although wide-bandgap semiconductors have emerged as a valuable class of deep-ultraviolet-sensitive materials, showing great potential for next-generation integrated devices, achieving high-performance deep-ultraviolet detectors without complicated designs at a low supply voltage and weak light intensity remains a significant challenge. Herein, we designed a new way to fabricate an ultrasensitive vertical-structured Ga₂O₃ photodetector with epitaxial oxygen-vacancy-rich In₂O₃ as the bottom conductive layer, which could realize the detection of rare weak deep-UV-light intensity (0.1 μW cm⁻²) at a voltage below 5 V, also demonstrating a surge in responsivity (36 A W⁻¹ at −4.8 V and 2.2 A W⁻¹ at 4.8 V) and detectivity (2 × 10¹³ Jones at −4.8 V and 4.4 × 10¹³ Jones at 4.8 V) with ultrafast response of 0.64 μs/47.68 μs (rise/decay). The ultrathin (15 nm) Ga₂O₃ layer and sophisticated band engineering, combined with suppression of the dark current through the interfacial oxygen vacancies on the In₂O₃ layer, enabled an enhancement of the detection performance of the detector at a low supply voltage and extremely low light intensity. These results provide a path towards highly sensitive, low-power-consumption and highly integrated deep-ultraviolet detection, beyond conventional ones.