STRAIN INDUCED CHANGE IN BAND OFFSETS AT PSEUDOMORPHICALLY GROWN INAS/GAAS HETEROINTERFACES CHARACTERIZED BY X-RAY PHOTOELECTRON-SPECTROSCOPY

We studied the heterojunction band offsets (HBOs) at highly-strained InAs/GaAs(100) heterointerfaces with an emphasis on the effects of strain. The core level energy differences between In 4d and Ga 3d levels in InAs/GaAs heterostructures are measured by in-situ X-ray photoelectron spectroscopy and found to be only slightly dependent on the substrate lattice constant. The effect of strain on the core level energies relative to the valence band maxima (VBM) was theoretically taken into account. The determined valence band offset DELTA-E(V)[ = E(V)(InAs)] is 0.53 eV on GaAs substrates and -0.16 eV on InAs substrates, clearly indicating a large effect of strain on the valence band offset (approximately 0.7 eV) in this system.