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 °C) fabricated a-Ga2O3 on a fused quartz, with ultrahigh UV response (208563.56 A/W at 250 nm@25 V), low Idark (0.59 pA@25 V), and ultrahigh signal-to-noise ratio (3.40 × 109 at 4.3 μW/cm2 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: tr1: 52.20 μs, tr2: 123.51 μs, recovery: td1: 1.61 ms, td2: 33.07 ms) of the device. The high density of the crystal/chaotic interfaces is the main reason for the low Idark 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 β-Ga2O3 detector but also possesses a much higher signal-to-noise ratio at faint deep-UV light than the complicated MOSFET β-Ga2O3 detector, which makes the low-temperature deposited a-Ga2O3 thin film an ideal material for developing ultrahigh-performance deep-UV detectors.