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Title: Ga and In adsorption on Si(112): Adsorption sites and superstructure

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 12; Related Information: CHORUS Timestamp: 2017-03-31 22:11:26; Journal ID: ISSN 2469-9950
American Physical Society
Country of Publication:
United States

Citation Formats

Speckmann, M., Schmidt, Th., Flege, J. I., Höcker, J., and Falta, J.. Ga and In adsorption on Si(112): Adsorption sites and superstructure. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.125441.
Speckmann, M., Schmidt, Th., Flege, J. I., Höcker, J., & Falta, J.. Ga and In adsorption on Si(112): Adsorption sites and superstructure. United States. doi:10.1103/PhysRevB.95.125441.
Speckmann, M., Schmidt, Th., Flege, J. I., Höcker, J., and Falta, J.. Fri . "Ga and In adsorption on Si(112): Adsorption sites and superstructure". United States. doi:10.1103/PhysRevB.95.125441.
title = {Ga and In adsorption on Si(112): Adsorption sites and superstructure},
author = {Speckmann, M. and Schmidt, Th. and Flege, J. I. and Höcker, J. and Falta, J.},
abstractNote = {},
doi = {10.1103/PhysRevB.95.125441},
journal = {Physical Review B},
number = 12,
volume = 95,
place = {United States},
year = {Fri Mar 31 00:00:00 EDT 2017},
month = {Fri Mar 31 00:00:00 EDT 2017}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.95.125441

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  • The pre-adsorption of Ga on Si(112) leads to a drastic change of the morphology of subsequently grown Ge islands. In contrast to the case for Ge growth on bare Si(112), even nanowire growth can be achieved on Ga terminated Si(112). Employing low energy electron microscopy and low energy electron diffraction, the initial phase of Ge nucleation and Ge island growth was systematically analysed for growth temperatures between 420 and 610 C, both on clean and on Ga terminated Si(112). In both cases the island density exhibits an Arrhenius-like behaviour, from which diffusion barrier heights of about 1.3 and 1.0 eVmore » can be estimated for growth with and without Ga pre-adsorption, respectively. The Ge island shape on the bare Si(112) surface is found to be nearly circular over the whole temperature range, whereas the shapes of the Ge islands on the Ga terminated Si(112) become highly anisotropic for higher temperatures. Ge nanowires with sizes of up to 2 um along the direction are observed.« less
  • We present an in-depth analysis of the atomic and electronic structure of the quasi-one-dimensional (1D) surface reconstruction of Ga on Si(112) based on scanning tunneling microscopy and spectroscopy (STM and STS), Rutherford-backscattering spectrometry (RBS), and density functional theory (DFT) calculations. A new structural model of the Si(112)6x1-Ga surface is inferred. It consists of Ga zigzag chains that are intersected by quasiperiodic vacancy lines or misfit dislocations. The experimentally observed meandering of the vacancy lines is caused by the coexistence of competing 6x1 and 5x1 unit cells and by the orientational disorder of symmetry breaking Si-Ga dimers inside the vacancy lines.more » The Ga atoms are fully coordinated, and the surface is chemically passivated. STS data reveal a semiconducting surface and show excellent agreement with calculated local density of states (LDOS) and STS curves. The energy gain obtained by fully passivating the surface calls the idea of step-edge decoration as a viable growth method toward 1D metallic structures into question.« less
  • The change of the Si(112) surface morphology and structure induced by In adsorption, as well as the impact of In preadsorption on the growth kinetics and island morphology in Ge/Si(112) epitaxy, has been investigated by means of low-energy electron microscopy and diffraction. The intrinsically faceted Si(112) surface is smoothed upon In saturation. In contrast to a previously reported (7 x 1) reconstruction (reported in a recent work of Gai et al.), we observe a [(3 + x) x 1] superstructure, with {approx} 1/2. This is attributed to the coexistence of (3 x 1) and (4 x 1) building blocks withmore » In vacancies. The presence of such vacancy rows is confirmed by the saturation of the [(3 + x) x 1] structure at about 0.8 monolayers. Ge growth on In-saturated Si(112) leads to the formation of 3-D islands, the morphology of which depends on the growth temperature. At 450 C, isotropic and dashlike islands are observed, whereas at 500 C, larger islands with a triangular outline are found. The orientation of the side facets of these triangular islands have been identified to be (111), (013), and (103). The dependence of the island density on the growth temperature indicates an enhanced Ge surface diffusion, as compared with growth on bare Si(112).« less