Ga₂O₃-Based Solar-Blind Position-Sensitive Detector for Noncontact Measurement and Optoelectronic Demodulation

As a kind of photodetector, position-sensitive-detectors (PSDs) have been widely used in noncontact photoelectric positioning and measurement. However, fabrications and applications of solar-blind PSDs remain yet to be harnessed. Herein, we demonstrate a solar-blind PSD developed from a graphene/Ga₂O₃ Schottky junction with a 25-nanometer-thick Ga₂O₃ film, in which the absorption of the nanometer-thick Ga₂O₃ is enhanced by multibeam interference. The graphene/Ga₂O₃ junction exhibits a responsivity of 48.5 mA/W and a rise/decay time of 0.8/99.8 μs at zero bias. Moreover, the position of the solar-blind spot can be determined by the output signals of the PSD. Using the device as a sensor of noncontact test systems, we demonstrate its application in measurement of angular, displacement, and light trajectory. In addition, the position-sensitive outputs have been used to demodulate optical signals into electrical signals. The results may prospect the application of solar-blind PSDs in measurement, tracking, communication, and so on.