Midwave infrared quantum dot avalanche photodiode

We report the first demonstration of a GaAs based avalanche photodiode (APD) operating in the midwave infrared region (3-5 mu m). In the device, called the quantum dot avalanche photodiode, an intersubband quantum dots-in-a-well detector is coupled with an APD through a tunnel barrier. Using this approach, we have increased the photocurrent and reached a conversion efficiency of 12%, which is one of the highest reported conversion efficiencies for any quantum dot detector. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3520519]