Digital Alloy Staircase Avalanche Photodetectors With Tunneling-Enhanced Gain

Y We report digital alloy AlxIn1-xAsySb1-y/GaSb staircase avalanche photodiodes (APDs) that operate using carriertrapping induced tunneling gain. Amodel describing carrier injection and escape fromnon-square quantum wells is presented to help explain and quantify the physics of carrier trapping in staircase APDstep regions. We showexperimental electrical and optical data demonstrating carrier trapping to corroborate thismodel. Furthermore, we derive electrostatic parameters that should be considered when designingAlInAsSb staircase APDs with low-noise and deterministic gain scaling that mitigate the deleterious effects of carrier trapping and tunneling in the staircase step regions.