Non-Markovian Hole Excess Noise in Avalanche Amorphous Selenium Thin Films.

Enhancing the signal-to-noise ratio in avalanche photodiodes by utilizing impact ionization gain requires materials exhibiting low excess noise factors. Amorphous selenium (-Se) as a wide bandgap at ∼2.1 eV, a solid-state avalanche layer, demonstrates single-carrier hole impact ionization gain and manifests ultralow thermal generation rates.

Modeling Dark Current Conduction Mechanisms and Mitigation Techniques in Vertically Stacked Amorphous Selenium-Based Photodetectors.

Amorphous selenium (-Se) with its single-carrier and non-Markovian, hole impact ionization process can revolutionize low-light detection and emerge to be a solid-state replacement to the vacuum photomultiplier tube (PMT). Although -Se-based solid-state avalanche detectors can ideally provide gains comparable to PMTs, their development has been severely limited by the irreversible breakdown of inefficient hole blocking layers (HBLs). Thus, understanding of the transport characteristics and ways to control electrical hot spots and, thereby, the breakdown voltage is key to improving the performance of avalanche -Se devices.