How to Use Type II InAs/GaSb Superlattice Structure to Reach Detection Wavelength of 2–3 $\mu{\rm m}$

The photoluminescence (PL) peak of an InAs/GaSb superlattice (SL) structure is found to be shifted from 5.8 to 4.0
$\mu{\rm m}$
at 77 K, when the growth temperature is lowered from 380 to 340
$^{\circ}{\rm C}$
. The PL peak shift is related to In intermixing, thus some SL structures cannot reach a detection wavelength
${<}{\rm 3}~\mu{\rm m}$
. Increasing the GaSb layer thickness in the SL structure is an effective way to reach a detection wavelength of 2–3
$\mu{\rm m}$
. A p-i-n detector with a 50% cutoff wavelength at 2.56
$\mu{\rm m}$
at 77 K is demonstrated.