Temperature Dependence of Avalanche Breakdown of AlGaAsSb and AlInAsSb Avalanche Photodiodes

Digital alloy Al _0.85 Ga _0.15 As _0.56 Sb _0.44 , random alloy Al _0.85 Ga _0.15 As _0.56 Sb _0.44 , and random alloy Al _0.79 In _0.21 As _0.74 Sb _0.26 are promising candidates for the multiplication regions of avalanche photodiodes (APDs) due to their low excess noise, which is comparable to that of Si APDs. The temperature dependence of avalanche breakdown in these materials has been investigated by measuring the multiplication gain. A weak temperature dependence of the breakdown voltage is observed, which is desirable to reduce the complexity of temperature or reverse bias control circuits in the optical receiver. Calculations of the alloy disorder potentials and alloy scattering rates indicate that the temperature dependence of the avalanche breakdown in these quaternary alloys is attributable to the dominance of large mass variations and high alloy scattering over phonon scattering. Impact ionization can also be impacted by the temperature dependence of the bandgap energy which affects the ionization threshold energy. Therefore, the temperature dependence of the bandgap energy has been investigated by temperature-dependent photoluminescence and external quantum efficiency measurements to further explain the temperature dependent breakdown characteristics of these materials.