X-RAY-PHOTOELECTRON-DIFFRACTION STUDY OF INAS/INP(001) HETEROSTRUCTURES

The growth mode and the strain of InAs thin films grown on InP(001) were measured by x-ray-photoelectron diffraction (XPD). Since the effects of a (2X4) reconstruction at the InAs film surface may drastically overlap those of the growth mode, we also investigated a (2X4) reconstructed GaAs(001) surface as a standard for this kind of reconstruction. It appears that this type of reconstruction does not induce significant effects on the polar angular distributions recorded within the (110) and the (110) planes. XPD measurements showed that the formation of thin InAs films on InP(001) by As stabilization is better described by a multilayer model of the InAs/InAsxP(1-x)/InP type than by a layer-by-layer InAs/InP model. For the strained 10-angstrom-thick InAs film grown on InP(001), the best agreement found between experiment and theory gives a vertical lattice expansion of 7.5%. This value is between 6.1%, the expansion obtained from the macroscopic linear elasticity theory, and 9.5%, the expansion obtained when assuming that the atomic bond length is retained.