X-ray photoemission core level determination of the GaSb/AlSb heterojunction valence-band discontinuity

The valence-band discontinuity ΔEv has been determined for the (100) GaSb/AlSb strained-layer heterojunction with a room-temperature lattice mismatch of 0.65%, using x-ray photoemission core level spectroscopy. For 30 Å epitaxial layers of AlSb grown on GaSb, the measured valence-band offset was ΔEv=0.40±0.15 eV. The reverse growth sequence consisting of a thin GaSb layer grown on an AlSb buffer exhibited the same valence-band offset, indicating that for the (100) oriented heterojunction ΔEv is not strongly affected by the growth sequence.