Zero Cross-Talk Geiger-Mode Avalanche Photodiode Arrays

There is provided an avalanche photodiode array that includes a plurality of avalanche photodiodes. Each avalanche photodiode in the array includes a stack of active photodiode materials. The stack of active photodiode materials includes a first electrical contact layer, a second electrical contact layer; an absorber material layer and an avalanche material layer each disposed between the first electrical contact layer and the second electrical contact layer; and an optical interface surface to the avalanche photodiode. The optical interface surface consists of an exposed surface of the first electrical contact layer, arranged for incident external radiation to directly enter the first electrical contact layer. Each avalanche photodiode stack of active photodiode materials is laterally isolated from the other avalanche photodiodes in the photodiode array.