Band offsets at the (1 0 0)GaSb/Al2O3 interface from internal electron photoemission study

From electron internal photoemission and photoconductivity measurements at the (1 0 0)GaSb/Al2O3 interface, the top of the GaSb valence band is found to be 3.05 ± 0.10 eV below the bottom of the Al2O3 conduction band. This interface band alignment corresponds to conduction and valence band offsets of 2.3 ± 0.10 eV and 3.05 ± 0.15 eV, respectively, indicating that the valence band in GaSb lies energetically well above the valence band of InxGa1−xAs (0 ⩽ x ⩽ 0.53) or InP.

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► Valence band of GaSb is up-shifted in energy as compared to GaAs.
► Photoelectron escape depth from GaSb into Al2O3 approaches 5 nm.
► O-derived VB top energy in oxides is weakly sensitive to the type of metal.
► Variation of the group V anion predominantly affects the VB energy in AIIIBV.