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 (2×4) reconstruction at the InAs film surface may drastically overlap those of the growth mode, we also investigated a (2×4) 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 (11¯0) 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/InAs_xP_(1-x)/InP type than by a layer-by-layer InAs/InP model. For the strained 10-Å-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.