Valence band offsets of Sc x Ga 1− x N/AlN and Sc x Ga 1− x N/GaN heterojunctions
Tsui, H C L and Goff, L E and Palgrave, R G and Beere, H E and Farrer, I and Ritchie, D A and Moram, M A
The valence band offsets of ScxGa1−xN/AlN heterojunctions were measured by x-ray photoelectron spectroscopy (XPS) and were found to increase from 0.42 eV to 0.95 eV as the Sc content x increased from 0 to 0.15. The increase in valence band offset with increasing x is attributed to the corresponding increase in spontaneous polarization of the wurtzite structure. The ScxGa1−xN/AlN heterojunction is type I, similar to other III-nitride-based heterojunctions. The data also indicate that a type II staggered heterojunction, which can enhance spatial charge separation, could be formed if ScxGa1−xN is grown on GaN.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK