Enhanced low-noise gain from InAs avalanche photodiodes with reduced dark current and background doping

We reduced the room temperature dark current in an InAs avalanche photodiode by increasing the p-type contact doping, resulting in an increased energetic barrier to minority electron injection into the p-region, which is a significant source of dark current at room temperature. In addition, by improving the molecular beam epitaxy growth conditions, we reduced the background doping concentration and realized depletion widths as wide as 5 mu m at reverse biases as low as 1.5 V. These improvements culminated in low-noise InAs avalanche photodiodes exhibiting a room temperature multiplication gain of similar to 80, at a record low reverse bias of 12 V. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757424]