Characterization of band offsets in AlxIn1-xAsySb1-y alloys with varying Al composition

The unprecedented wide bandgap tunability (similar to 1 eV) of AlxIn1-xAsySb1-y lattice-matched to GaSb enables the fabrication of photodetectors over a wide range from near-infrared to mid-infrared. In this paper, the valence band-offsets in AlxIn1-xAsySb1-y with different Al compositions are analyzed by tight binding calculations and X-ray photoelectron spectroscopy measurements. The observed weak variation in valence band offsets is consistent with the lack of any minigaps in the valence band, compared to the conduction band.