Optical vibrational and structural properties of Ge 1-xSn x alloys by UHV-CVD

Jennifer Taraci, S. Zollner, Martha McCartney, Jose Menendez, David Smith, John Tolle, M. Bauer, Erika Duda, N. V. Edwards, John Kouvetakis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


UHV-CVD growth based on a deuterium stabilized Sn hydride and digermane produces Ge-Sn alloys with tunable bandgaps. The Ge 1-xSn x (x=2-20 at.%) alloys are deposited on Si (100) and exhibit superior crystallinity and thermal stability compared with MBE grown films. Composition, crystal and electronic structure, and optical and vibrational properties are characterized by RBS, low energy SIMS, high resolution electron microscopy TEM, x-ray diffraction, as well as Raman and IR spectroscopies. TEM studies reveal epitaxial films with lattice constants between those of Ge and Sn. X-ray diffraction shows well-defined (004) peaks and rocking curves indicate a tightly aligned spread of the crystal mosaics. Resonance Raman indicate a E 1 bandgap reduction relative to Ge, consistent with a decrease of the E 2 critical point observed in spectroscopic ellipsometry. IR transmission spectra indicate an increase in absorption with increasing Sn content consistent with a decrease of the direct bandgap.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsE Jones, O Manasreh, K Choquette, D Friedman, D Johnstone
Number of pages6
StatePublished - 2002
EventProgress in Semiconductor Materials for Optoelectronic Applications - Boston, MA, United States
Duration: Nov 26 2001Nov 29 2001


OtherProgress in Semiconductor Materials for Optoelectronic Applications
Country/TerritoryUnited States
CityBoston, MA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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