Gas Source Techniques for Molecular Beam Epitaxy of Highly Mismatched Ge Alloys
by
Chad A. Stephenson 1,*
, Miriam Gillett-Kunnath 2, William A. O’Brien 3, Robert Kudrawiec 4 and Mark A. Wistey 1
Chad A. Stephenson 1,*, Miriam Gillett-Kunnath 2, William A. O’Brien 3, Robert Kudrawiec 4 and Mark A. Wistey 1
1
Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
2
Department of Chemistry, Syracuse University, Syracuse, NY 13244, USA
3
Rigetti Quantum Computing, 775 Heinz Avenue, Berkeley, CA 94710, USA
4
Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
*
Author to whom correspondence should be addressed.
Academic Editor: Paul J. Simmonds
Crystals 2016, 6(12), 159; https://doi.org/10.3390/cryst6120159
Received: 21 October 2016 / Revised: 19 November 2016 / Accepted: 21 November 2016 / Published: 2 December 2016
(This article belongs to the Special Issue Current and Future Directions in Crystal Growth by Molecular Beam Epitaxy (MBE))
Ge and its alloys are attractive candidates for a laser compatible with silicon integrated circuits. Dilute germanium carbide (Ge1−xCx) offers a particularly interesting prospect. By using a precursor gas with a Ge4C core, C can be preferentially incorporated in substitutional sites, suppressing interstitial and C cluster defects. We present a method of reproducible and upscalable gas synthesis of tetrakis(germyl)methane, or (H3Ge)4C, followed by the design of a hybrid gas/solid-source molecular beam epitaxy system and subsequent growth of defect-free Ge1−xCx by molecular beam epitaxy (MBE). Secondary ion mass spectroscopy, transmission electron microscopy and contactless electroreflectance confirm the presence of carbon with very high crystal quality resulting in a decrease in the direct bandgap energy. This technique has broad applicability to growth of highly mismatched alloys by MBE.
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Keywords:
germanium; germanium carbide; molecular beam epitaxy
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MDPI and ACS Style
Stephenson, C.A.; Gillett-Kunnath, M.; O’Brien, W.A.; Kudrawiec, R.; Wistey, M.A. Gas Source Techniques for Molecular Beam Epitaxy of Highly Mismatched Ge Alloys. Crystals 2016, 6, 159.
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