【Device Papers】Ga₂O₃-based Solar-Blind Deep-UV Detector With ~10⁷ Rejection Ratio: Insights Into Temperature-Dependent Carrier Dynamics

      Researchers from IIT Guwahati have published a dissertation titled " Ga₂O₃-based Solar-Blind Deep-UV Detector With ~10⁷ Rejection Ratio: Insights Into Temperature-Dependent Carrier Dynamics " in IEEE Transactions on Electron Devices.

Abstract

      Ultrawide-bandgap Ga₂O₃ is well suited for solar-blind deep-UV detection, enabling direct sensing without filters or complex structures. While most devices use the β phase, other phases are less explored, especially at high temperatures. This work reports fabrication and temperature-dependent characterization of a solar-blind deep-ultraviolet (DUV) metal–semiconductor–metal (MSM) photodetector based on α-Ga₂O₃-dominated thin films grown on c-plane sapphire by a mist chemical vapor deposition (mist-CVD) system at relatively lower temperatures to reduce the carbon footprint of the developed technology. At room temperature and 30-V bias, the detector shows an ultralow dark current of ~3.3×10^-13 A. Under 230-nm illumination with a low optical power density of ~8 um/cm²，the device achieves a responsivity of ~7 A/W, a photo-to-dark current ratio (PDCR) on the order of ~10⁵，and a record-high UV-to-visible rejection ratio of ~10⁷ (230/500 nm), confirming strong solar-blind selectivity. Device behavior was further examined from 25℃ to 300℃ to evaluate suitability for harsh environments. With increasing temperature, the dark current rises and the photocurrent initially decreases, then increases due to thermally generated carriers, trap effects, and phonon scattering. The dominant photocurrent transport pathways were identified by extracting activation energies from Arrhenius plots of the temperature-dependent rise and decay components. Even at 300℃，the detector maintains a measurable response, with a responsivity of ~0.17 A/W and PDCR of 2.77, and shows stable operation over repeated heating cycles. These results show that α-Ga₂O₃-dominated MSM photodetectors enable reliable DUV sensing over a wide temperature range, promising for high-temperature solar-blind applications.

DOI：

https://doi.org/10.1109/TED.2026.3733916