Fig. 3: Current–voltage, measured gain and excess noise measurements.

a, Measured current–voltage and gain curves of a 100-µm-diameter device at room temperature. b, Measured gain curves of the device at 240 K with different optical attenuations. c, Measured excess noise factors of the device under 2 µm illumination; the solid line shows the theoretical excess noise factors for k values from 0.01 to 0.20. d, Measured dark current density at various temperatures; the dark current densities of the state-of-the-art 2 µm HgCdTe APD⁸ and AlInAsSb APD¹¹ are plotted for reference.