Low excess noise HgCdTe e-SWIR avalanche photodiode operating at high gain and temperature

The Hg1−xCdxTe material can exhibit a pure electron avalanche when the composition of the Cd is below 0.6. This hole-to-electron impact ionization ratio close to zero results in noiseless gain. In this paper, we present the results on the gain and noise characteristics of the extended short wavelength infrared (e-SWIR) HgCdTe electron-initialed avalanche photodiodes (e-APDs). The e-APD has a Cd composition of 0.4 and a cutoff wavelength of 3.1μm. At 80K with a bias voltage of -18.5V, the device achieves a remarkable gain of 1080, with an excess noise factor below 1.6. Furthermore, the device maintains a gain of 550 and an excess noise below 1.6 at 220K. Notably, this work reports for the first time the low noise performance of the device at high temperatures and high gain. Moreover, we investigate the responsivity and detectivity of the device when operating at the unit gain point.