High-performance Ga₂O₃-based solar-blind UV photodetectors developed with low fabricating and operating temperature

Infrared and ultraviolet dual-band integrated detectors are among the most important development trends in photodectors. To be compatible with the low operating and mild fabricating temperature for cooled infrared detectors, it is crucial to develop low-temperature operating UV photodetectors with mild fabricating conditions. In this work, we developed amorphous Ga₂O₃-based metal-semiconductor-metal solar-blind UV photo-detectors with a low temperature process no higher than 200°C. The photodetectors fabricated with the low-temperature annealed ALD-Ga₂O₃ thin films exhibit an ultra-low dark current of 5.04 × 10^-14 A, high photo-to-dark current ratio of 1.09 × 10⁷, high detectivity of 6.5 × 10¹⁵ Jones and responsivity of 1.04 A/W at bias of 5 V. The rise and decay times are less than 70 ms. The changes of oxygen vacancy defects and crystallization region are probably the main reasons. Besides, the prepared photodetectors represent the photo-to-dark current ratio of 2.04 × 10⁵, detectivity of 4.8 × 10¹⁴ Jones, and responsivity of 0.13 A/W at liquid nitrogen temperature. Further, the optimal UV photodetectors were integrated with HgCdTe infrared photodetector realizing solar blind UV and short infrared detecting by a single device. This work provides some ideas for exploiting the low-temperature fabricating process of Ga₂O₃-based UV photodetectors and widening its low-temperature application scenarios. It also lays a foundation for integrating with a cooled infrared detector.