Structure of metal-rich (001) surfaces of III-V compound semiconductors

Abstract

The atomic structure of the group-III-rich surface of III-V semiconductor compounds has been under intense debate for many years, yet none of the models agrees with the experimental data available. Here we present a model for the three-dimensional structure of the (001)-c(8ϫ2) reconstruction on InSb, InAs, and GaAs surfaces based on surface x-ray diffraction data that was analyzed by direct methods and subsequent least squares refinement. Contrary to common belief the main building blocks of the structure are not dimers on the surface but subsurface dimers in the second bilayer. This essential feature of the structure is accompanied by linear arrays of atoms on nonbulklike sites at the surface which, depending on the compounds, exhibit a certain degree of disorder. A tendency to group-III-dimer formation within these chains increases when descending the periodic table. We propose that all the c(8ϫ2) reconstructions of III-V semiconductor surfaces contain the same essential building blocks.

Lateral resolution and potential sensitivity in Kelvin probe force microscopy: Towards understanding of the sub-nanometer resolution

“…Based on earlier studies, the presented topography structure image is recognized as the image of the surface indium sublattice, 13 where the dominant indium chains, labeled In1, protrude about 1.2 Å over the rest of the surface. It should be noted here that, according to a model of reconstructed ͑001͒ surfaces of AIIIBV semiconductor compounds, 24 the In1 atoms protrude of about 0.9 Å over the neighboring surface atoms. Thus, it is assumed that the imaging of the InSb͑01͒ surface in the constant detuning mode traces the surface with the relative changes of the tip-surface distance over atomic sites of about 0.3 Å.…”

Unusual Bi-Containing Surface Layers of III–V Compound Semiconductors

“…Dimers can be formed by atoms of the same element (homodimers) or different elements (heterodimers). However, dimers can be formed also in the subsurface layer [27][28][29]. Thus, usually by dimer one means a pair of atoms which form a bond (in parallel to the surface) which is not characteristic for the underlying bulk.…”

“…The atomic structure of these III-V(100)c(8 × 2) surfaces has been widely accepted to be one of the two structures shown in Fig. 10.10 or their combination [27][28][29]83]. The GaAs(100)c(8 × 2) surface has the ξ structure while the InAs(100)c(8 × 2) has the ξa structure rather than the ξ one.…”

Adsorption and diffusion of a Cl adatom on the GaAs(001)-c(8×2)ζsurface

“…Subsequently, this predicted structure was confirmed by analyses of STM, low-energy electron diffraction, and surface x-ray diffraction. [21][22][23] In this novel structure, the excess Ga atoms are located below the surface layer. Thus, from the vacuum side the surface looks as if it is As rich.…”

“…Recently such reconstruction, though with a noticeable amount of disordered group-III surface vacancies, was also suggested to exist for other III-V surfaces such as InAs and InSb. 22,23 The adsorption and etching processes of the GaAs surface with Cl, the most common etchant, has been extensively investigated in the literature, and Cl 2 is known to adsorb dissociatively. 3,4,7,24,25 Recently McLean et al reported a systematic STM study on chlorine adsorption and diffusion on GaAs͑001͒ c(8ϫ2).…”