Extended X-ray Absorption Fine Structure investigation on buried InAsP/InP interfaces

As K-edge extended x-ray absorption fine structure has been carried out on the 2-3 monolayers thick interface of ad hoc grown InAsP/InP expitaxial multistructures deposited by low pressure metalorganic vapor phase epitaxy. The goal was to characterize the local structure of the unwanted,strained interface layers of InAsP produced by the exposure of the InP surface to AsH3 as occurs during the growth of InP/InGaAs heterostructures. We observed that the first shell environment of As at these interfaces is identical to that found in bulk InAs. In particular,we measure a constant As-In bond length,independently of As concentration at the interface; this implies that epitaxy with InP is accompanied by local structural distortions which accommodate the constant As-In bond length.