Synthesis of Ge1−xSnx alloys by ion implantation and pulsed laser melting: Towards a group IV direct bandgap material
- 11 May 2016
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 119 (18), 183102
- https://doi.org/10.1063/1.4948960
Abstract
The germanium-tin (Ge1−xSnx) material system is expected to be a direct bandgap group IV semiconductor at a Sn content of . Such Sn concentrations can be realized by non-equilibrium deposition techniques such as molecular beam epitaxy or chemical vapour deposition. In this report, the combination of ion implantation and pulsed laser melting is demonstrated to be an alternative promising method to produce a highly Sn concentrated alloy with a good crystal quality. The structural properties of the alloys such as soluble Sn concentration, strain distribution, and crystal quality have been characterized by Rutherford backscattering spectrometry, Raman spectroscopy, x ray diffraction, and transmission electron microscopy. It is shown that it is possible to produce a high quality alloy with up to . The optical properties and electronic band structure have been studied by spectroscopic ellipsometry. The introduction of substitutional Sn into Ge is shown to either induce a splitting between light and heavy hole subbands or lower the conduction band at the valley. Limitations and possible solutions to introducing higher Sn content into Ge that is sufficient for a direct bandgap transition are also discussed.
Keywords
Funding Information
- Australian Research Council, Australia
- National Collaborative Research Infrastructure Strategy
This publication has 47 references indexed in Scilit:
- Investigation of the direct band gaps in Ge1−xSnx alloys with strain control by photoreflectance spectroscopyApplied Physics Letters, 2012
- Possibility of increased mobility in Ge-Sn alloy systemPhysical Review B, 2007
- Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrateJournal of Applied Physics, 2005
- Interband Transitions inAlloysPhysical Review Letters, 1997
- Electronic properties of metastablealloysPhysical Review B, 1987
- Excitonic effect in the optical spectrum of semiconductorsPhysical Review B, 1985
- Dielectric functions and optical parameters of Si, Ge, GaP, GaAs, GaSb, InP, InAs, and InSb from 1.5 to 6.0 eVPhysical Review B, 1983
- Numerical error analysis of derivative spectrometry for the quantitative analysis of mixturesAnalytical Chemistry, 1976
- Electroreflectance Spectra and Band Structure of GermaniumPhysical Review B, 1968
- Fourier Expansion for the Electronic Energy Bands in Silicon and GermaniumPhysical Review B, 1967