Structure determination for the (110) surface of zincblende structure compound semiconductors

Abstract

A survey is presented of determinations of the atomic geometries of the (110) surfaces of zincblende-structure III–V and II–VI compounds via analyses of elastic low-energy electron diffraction intensities, of both integrated and angle-resolved ultraviolet photoemission spectra, and of electron paramagnetic resonance signals associated with adsorbed O−2 complexes. Comparison of the proposed model geometries for GaAs(110) reveals that they are compatible both with each other to within the accuracy of the analytical methodologies and with energy-minimization calculated structures. Results for other materials are fragmentary, but suggest incompatibilities between spectroscopically-determined and energy-minimized structures for ZnTe(110) and InSb(110). All of the model surface structures embody large movements of species in the uppermost atomic layer, with the cation moving inward by Δd⊥?0.4 A and the anion outward either less or not at all. The reconstructions penetrate to the second and perhaps third atomic layer for covalently bonded materials like GaAs and InSb. Spectroscopic evidence for the penetration of the reconstructions beneath the top layer is weak, however, for more ionic compounds like ZnTe.