Characteristics Measurement in a Deep UV Single Photon Detector Based on a TE-cooled 4H-SiC APD

We report on the characteristics of a lab-assembled UV single photon detector based on a thermoelectrically cooled silicon carbide (4H-SiC) avalanche photodiode (APD). The SiC- APD in this experiment was fabricated with a beveled mesa structure, with electronics designed to achieve passive Geiger-mode operation and to convert the avalanche signal to a transistor–transistor logic signal by readout backend. We attached the SiC-APD to a 4-stage thermoelectric cooler to vary APD temperature from 25 °C to −30 °C, and investigated dark count rates according to applied bias voltage at different temperatures. Breakdown voltages applied to the SiC-APD were also measured while adjusting APD temperature. Finally, we evaluated afterpulse characteristics through the time-correlated single-photon counting method, and observed that afterpulsing probability increases with decreasing APD temperature.