Gas Source Techniques for Molecular Beam Epitaxy of Highly Mismatched Ge Alloys




Stephenson, Chad A.
Gillett-Kunnath, Miriam
O'Brien, William A.
Kudrawiec, Robert
Wistey, Mark A.

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Multidisciplinary Digital Publishing Institute


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.


This article belongs to the Special Issue Current and Future Directions in Crystal Growth by Molecular Beam Epitaxy.


germanium, germanium carbide, molecular beam epitaxy, Physics


Stephenson, C. A., Gillett-Kunnath, M., O’Brien, W. A., Kudrawiec, R. & Wistey, M. A. (2016). Gas Source Techniques for Molecular Beam Epitaxy of Highly Mismatched Ge Alloys. Crystals, 6, 159.


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