Measurement of AlAs/InP and InP/In0.52Al0.48As heterojunction band offsets by x-ray photoemission spectroscopy

X-ray photoemission spectroscopy (XPS) has been used to measure the valence band offsets at the x=0 and x=0.52 points of the InxAl1−xAs/InP(100) heterojunction system. For the lattice-matched interface we determine a value of ΔEv(InP/In0.52Al0.48As)=0.16 eV (staggered band alignment). Although the pseudomorphic AlAs/InP(100) interface investigated is strained, the ΔEv(AlAs/InP)=−0.27 eV (nested band alignment) value obtained by the XPS analysis method used is interpreted as being characteristic of an unstrained interface.