Band offsets of Al_2O_3/In_xGa_(1-x)As (x=0.53 and 0.75) and the effects of postdeposition annealing

摘要

Band offsets at the interfaces of In_xGa_(1-x)As/Al_2O_3/Al where x=0.53 and 0.75 were determined by internal photoemission and spectroscopic ellipsometry. The photoemission energy threshold at the In_xGa_(1-x)As/Al_2O_3 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.