Nano scale phase separation in Au-Ge system on ultra clean Si(100) surfaces

2012/02/03 by Ashutosh Rath, J. K. Dash, R. R. Juluri +4 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1063/1.4721666

published as J. Appl. Phys. 111, 104319 (2012);arXiv:1202.0614 · 23 pages, 6 Figures, 1 Table

arxiv created 2012/02/03 · arxiv updated 2017/11/27

Abstract

We report on the formation of lobe-lobe (bi-lobed) Au-Ge nanostructures under ultra high vacuum (UHV) conditions (≈ 3× 10^-10 mbar) on clean Si(100) surfaces. For this study, ≈ 2.0 nm thick Au samples were grown on the substrate surface by molecular beam epitaxy (MBE). Thermal annealing was carried out inside the UHV chamber at temperature \apprx 500°C and following this, nearly square shaped Au_xSi_1-x nano structures of average length ≈ 48 nm were formed. A ≈ 2 nm Ge film was further deposited on the above surface while the substrate was kept at a temperature of ≈ 500°C. Well ordered Au-Ge nanostructures where Au and Ge residing side by side (lobe-lobe structures) were formed. In our systematic studies, we show that, gold-silicide nanoalloy formation at the substrate (Si) surface is necessary for forming phase separated Au-Ge bilobed nanostructures. Electron microscopy (TEM, STEM-EDS, SEM) studies were carried out to determine the structure of Au - Ge nano systems. Rutherford backscattering Spectrometry measurements show gold inter-diffusion into substrate while it is absent for Ge.

Cited by

• Gold assisted molecular beam epitaxy of Ge nanostructures on Ge(100) Surface

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