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

Wide bandgap semiconductors have emerged as a valuable class of deep-ultraviolet sensitive materials, showing great potential for next-generation integrated devices. Yet, to achieve a high performance of deep-ultraviolet detector without complicated designs at low supply voltage and weak light intensity has proven challenging. Herein, we design a new way to fabricate an ultrasensitive vertical-structured Ga2O3 photodetector with epitaxial oxygen-vacancy-rich In2O3 as the bottom conductive layer, realizing the detection to a rare weak deep UV light intensity (0.1 μW/cm²) at a voltage below 5 V, and demonstrating a surge in responsivity (36 A/W at -4.8 V and 2.2 A/W 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). Ultrathin (15 nm) Ga2O3 layer and sophisticated band engineering, combined with suppressed dark current through the interfacial oxygen vacancies on In2O3 layer, enhance the detection performance of the detector at 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.