Demonstration of an avalanche drift detector with front illumination

An avalanche drift detector with photon counting capability is proposed and demonstrated. It combines the drift structure with a “point-like” Geiger mode avalanche diode, which is used as the collecting electrode. The diameters of the front entrance window and the avalanche diode of the fabricated detector are 294 and 10 μm, respectively, and the thickness of the whole depletion region is below 10 μm. Experimental results show that the dark count rate is 19.34 kHz at room temperature and is reduced to 2.78 kHz when the temperature decreases to −40 °C. When the light pulse frequency is below the saturation value of 140 kHz at room temperature, the average increase of the electrical signal frequency is about 3.5 kHz with a 10 kHz increase of the light pulse frequency.