Type-II superlattice photodetector on a compliant GaAs substrate

A type-II superlattice (SL) of InAs-InGaSb has been grown on a compliant GaAs substrate by molecular beam epitaxy. This SL was designed for photoconductive infrared (IR) detection in the long wavelength IR band. The spectral photoresponse of this SL shows a sharp onset at 76.9 meV and a corresponding cutoff wavelength at 13.9 μm. A sixfold increase in the peak photoresponse was measured in comparison to the response from a similar SL on a standard GaSb substrate.