Abstract
A method for studying heterojunction band lineups on the submicrometer scale is demonstrated by using synchrotron-radiation photoelectron microscopy and spectroscopy. In particular, an in situ sample cleavage technique is adopted here to reveal the cross-sectional, nonpolar a -plane face of InNGaN heterojunction grown on Si(111) along the polar -c axis with fully relaxed lattice structure, eliminating the polarization effects associated with the interface charge/dipole normal to the cleaved surface. The "intrinsic" valence band offset at the cleaved InNGaN heterojunction has been determined to be 0.78 eV. Additionally, using known material parameters, the values of InNGaN conduction band offset and InN electron affinity are also estimated. © 2008 American Institute of Physics.