Surface electronic properties of undoped InAlN alloys

The variation in surface electronic properties of undoped c-plane InxAl1-xN alloys has been investigated across the composition range using a combination of high-resolution x-ray photoemission spectroscopy and single-field Hall effect measurements. For the In-rich alloys, electron accumulation layers, accompanied by a downward band bending, are present at the surface, with a decrease to approximately flatband conditions with increasing Al composition. However, for the Al-rich alloys, the undoped samples were found to be insulating with approximate midgap pinning of the surface Fermi level observed. (C) 2008 American Institute of Physics.