Direct-gap Ge/GeSn/Si and GeSn/Ge/Si heterostructures

✍ Scribed by Richard A. Soref; Lionel Friedman

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 159 KB
• Volume: 14
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1993.1122

✦ Synopsis

A theoretical proposal is given for creating direct-gap semiconductor layers in silicon-based Group IV heterostructures. Based upon recent bandstructure calculations for pseudomorphic (\mathrm{Ge} / \mathrm{GeSi}) and (\mathrm{GeSi} / \mathrm{Ge}), we predict a strain-induced (\Gamma^{\mathrm{C}})-L (\mathrm{L}^{\mathrm{c}}) direct-gap crossover ((\lambda \mathrm{g} \sim 2.2 \mu \mathrm{m})) in tensile (\mathrm{Ge} / \mathrm{Ge}{0.87} \mathrm{Sn}{0.13}) and in compressive (\mathrm{Ge}{0.98} \mathrm{Sn}{0.02} / \mathrm{Ge}). We used linear extrapolation of band-edge curves. The direct-gap structures are potentially useful in laser diodes, electrooptic modulators, and photodetectors.