Direct gap group IV semiconductors for next generation Si-based IR photonics

John Kouvetakis, James Gallagher, Jose Menendez

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

1 Scopus citations


This paper presents synthesis and optical properties of mono-crystalline Ge 1-ySn y and Ge 1-x-ySi xSn y semiconductor alloys grown on Si/Ge platforms via purposely designed CVD routes using highly reactive Si/Ge/Sn hydrides including Ge 3H 8, Ge 4H 10, Si 4H 10 and SnD 4. The Ge 1-ySn y materials are shown to exhibit strong and tunable photoluminescence induced by the substitution of sizable Sn concentrations in the Ge diamond lattice ultimately leading to an indirect-to-direct band gap crossover at y= 0.08-0.09. The optical data indicate that the IR coverage of the alloy extends well beyond that of elemental Ge into the broader long wavelength range suggesting a variety of applications in Si-based photonics. Ge 1-x-ySi xSn y alloys represent the first viable ternary semiconductor among group IV elements with independently tunable lattice parameter and electronic structure. Studies of the compositional dependence of direct and indirect edges in these alloys using photoluminescence and photocurrent measurements are reviewed. The optical results show band gap variation over a wide range above and below that of Ge from 1.1 to 0.5 eV and provide the first demonstration of direct gap behavior in this semiconductor system.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings
PublisherMaterials Research Society
StatePublished - 2014
Event2014 MRS Spring Meeting - San Francisco, United States
Duration: Apr 21 2014Apr 25 2014


Other2014 MRS Spring Meeting
Country/TerritoryUnited States
CitySan Francisco


  • photoconductivity
  • photoemission
  • semiconducting

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials


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