Hofmann, EVS;
Scalise, E;
Montalenti, F;
Stock, TJZ;
Schofield, SR;
Capellini, G;
Miglio, L;
... Klesse, WM; + view all
(2021)
The formation of a Sn monolayer on Ge(1 0 0) studied at the atomic scale.
Applied Surface Science
, 561
, Article 149961. 10.1016/j.apsusc.2021.149961.
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Abstract
The growth of multi-layer germanium-tin (GeSn) quantum wells offers an intriguing pathway towards the integration of lasers in a CMOS platform. An important step in growing high quality quantum well interfaces is the formation of an initial wetting layer. However, key atomic-scale details of this process have not previously been discussed. We use scanning tunneling microscopy combined with density functional theory to study the deposition of Sn on Ge(1 0 0) at room temperature over a coverage range of 0.01 to 1.24 monolayers. We demonstrate the formation of a sub-2% Ge content GeSn wetting layer from three atomic-scale characteristic ad-dimer structural components, and show that small quantities of Sn incorporate into the Ge surface forming two atomic configurations. The ratio of the ad-dimer structures changes with increasing Sn coverage, indicating a change in growth kinetics. At sub-monolayer coverage, the least densely packing ad-dimer structure is most abundant. As the layer closes, forming a two-dimensional wetting layer, the more densely packing ad-dimer structure become dominant. These results demonstrate the capability to form an atomically smooth wetting layer at room temperature, and provide critical atomic-scale insights for the optimization of growth processes of GeSn multi-quantum-wells to meet the quality requirements of optical GeSn-based devices.
| Type: | Article |
|---|---|
| Title: | The formation of a Sn monolayer on Ge(1 0 0) studied at the atomic scale |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.apsusc.2021.149961 |
| Publisher version: | https://doi.org/10.1016/j.apsusc.2021.149961 |
| Language: | English |
| Additional information: | © 2021 The Authors. Published by Elsevier B.V. under a Creative Commons license (https://creativecommons.org/licenses/by/4.0/). |
| Keywords: | STM,DFT, GeSn, Wetting layer |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10128453 |
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