Demonstrating the β-Ga2O3 Schottky diodes for alpha radiation detection

Abstract

Schottky barrier diodes were fabricated on (001) monoclinic β-Ga2O3 wafers with low doped epitaxial layers of 7.0 × 1015 cm−3. Circular Ni Schottky contacts with area 2 mm2 were deposited by electron beam evaporation. Devices were characterized electrically by performing forward and reverse current-voltage sweeps with a range of −100 V–2 V, as well as capacitance-voltage sweeps to −30 V. The breakdown voltage was also determined to be −180 V for the devices. Experiments measuring the electrical response from incident X-ray radiation was performed. A response time to X-ray radiation of less than 1 s was recorded and a decay time of approximately 2 s after removing X-ray source, which primarily attribute to X-ray switching on and off time. Energy spectra of alpha particles from a 0.9 μCi 241Am button source was collected at various voltage biases using devices with the lowest measured leakage current while reverse biased. The total count rate was observed to increase linearly with increasing device bias. The peak channel number was observed to increase with increasing bias with the best resolution of 9.5% at −100 V reverse bias.