Band offsets of Al2O3/InxGa1-xAs (x=0.53 and 0.75) and the effects of postdeposition annealing

摘要

Band offsets at the interfaces of InxGa1-xAs/Al2O3/Al where x=0.53 and 0.75 were determined by internal photoemission and spectroscopic ellipsometry. The photoemission energy threshold at the InxGa1-xAs/Al2O3 interface was found to be insensitive to the indium composition but shifted to a lower energy after a postdeposition annealing at high temperatures. Subthreshold electron photoemission was also observed for the annealed sample and was attributed to interfacial layer formation during the annealing process.