How to Use Type II InAs/GaSb Superlattice Structure to Reach Detection Wavelength of 2–3

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.