InSb Avalanche Photodiodes on GaAs Substrates for Mid-Infrared Detection

We present indium antimonide-based devices for mid-infrared (mid-IR) detection with enhanced sensitivity. InSb devices will be useful for many applications, such as gas sensing and imaging. InSb avalanche photodiodes (APDs) monolithically integrated with GaAs substrates were fabricated with diameters ranging from 90 to 200 μm and extensively characterized at temperatures ranging from 77 K to 300 K. At 120 K a zero-bias responsivity of 2 A/W was measured, corresponding to a quantum efficiency of 55%. An experimental gain value of 10 at a reverse bias of -3 V was obtained at 120 K, which to the best of our knowledge, is the highest ever reported for InSb APDs. These results pave the way for the development of a monolithically integrated mid-IR array with added gain and wavelength tunability.