UV Response Characteristics of Amorphous Ga₂O₃ Thin Films With Different Microatom Distributions and a Low-Temperature Fabricated Ultrahigh-Performance a-Ga₂O₃ UV Detector

It is very difficult to achieve an ultrahigh response and signal-to-noise ratio in a solar-blind UV (220-280 nm) detector, which is extremely important in its actual applications in many fields (e.g., alarm, biological, and information). Herein, through systematic study on UV response characteristics of amorphous-Ga2O3 (a-Ga2O3) films with different microstructures, a simple metal-semiconductor-metal structure detector based on low-temperature (500 degrees C) fabricated a-Ga2O3 on a fused quartz, with ultrahigh UV response (208563.56 A/W at 250 nm@25 V), low I-dark (0.59 pA@25 V), and ultrahigh signal-to-noise ratio (3.40 x 10(9) at 4.3 mu W/cm(2) 250 nm @25 V) simultaneously, is reported. A new two-step tunneling breakdown mechanism in a-Ga2O3 with a high density of scattered distributed small crystal nanoparticles introduced both ultrahigh UV response and fast speeds (response: t(r1): 52.20 mu s, t(r2): 123.51 mu s, recovery: t(d1): 1.61 ms, t(d2): 33.07 ms) of the device. The high density of the crystal/chaotic interfaces is the main reason for the low I-dark and ultrahigh signal-to-noise ratio of the a-Ga2O3 UV detector. In addition, the a-Ga2O3 detector not only has a higher deep-UV response than the crystalline beta-Ga2O3 detector but also possesses a much higher signal-to-noise ratio at faint deep-UV light than the complicated MOSFET beta-Ga2O3 detector, which makes the low-temperature deposited a-Ga2O3 thin film an ideal material for developing ultrahigh-performance deep-UV detectors.