Accession Number:

ADP012672

Title:

Optical Vibrational and Structural Properties of Ge1-xSnx Alloys by UHV-CVD

Descriptive Note:

Symposium proceedings

Corporate Author:

ARIZONA STATE UNIV TEMPE DEPT OF CHEMISTRY

Report Date:

2002-01-01

Pagination or Media Count:

6.0

Abstract:

UHV-CVD growth based on a deuterium stabilized Sn hydride and digermane produces Ge-Sn alloys with tunable bandgaps. The Ge1-xSnx x2-20 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 E1 bandgap reduction relative to Ge, consistent with a decrease of the E2 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.

Subject Categories:

  • Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE