MWIR InSb detector with nBn architecture for high operating temperature

摘要

In this communication, we report results obtained on a new InSb/InAlSb/InSb 'bariode', grown by MBE on (100)-oriented InSb substrate. Because of a very weak valence band offset with InSb (～ 25meV), InAlSb is a good candidate as a barrier layer for electrons. However, due to lattice mismatch with the InSb substrate, careful growth study of InAlSb was made to insure high crystal quality. As a result, InSb-based nBn detector device exhibits dark current density equals to 1×10~(-9)A.cm~(-2) at 77K: two decades lower than Insb standard pin photodiode with similar cut-off wavelength. Moreover, compared to standard pn (or pin) InSb-based photodetectors fabricated by implanted planar process or by molecular beam epitaxy (MBE), we demonstrate that the reachable working temperature, around 120 K, of the InSb-based nBn detector is respectively higher than 40 K and 20 K than the previous. Such result demonstrates the potentiality of Insb detectors with nBn architecture to reach the high operating temperature.