Increased photoluminescence of strain-reduced, high-Sn composition Ge{sub 1-x}Sn{sub x} alloys grown by molecular beam epitaxy
- Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)
- Stanford Nano Center (SNC), Stanford University, Stanford, California 94305 (United States)
We synthesized up to Ge{sub 0.914}Sn{sub 0.086} alloys on (100) GaAs/In{sub y}Ga{sub 1-y}As buffer layers using molecular beam epitaxy. The buffer layers enable engineered control of strain in the Ge{sub 1-x}Sn{sub x} layers to reduce strain-related defects and precipitation. Samples grown under similar conditions show a monotonic increase in the integrated photoluminescence (PL) intensity as the Sn composition is increased, indicating changes in the bandstructure favorable for optoelectronics. We account for bandgap changes from strain and composition to determine a direct bandgap bowing parameter of b = 2.1 {+-} 0.1. According to our models, these are the first Ge{sub 1-x}Sn{sub x} samples that are both direct-bandgap and exhibit PL.
- OSTI ID:
- 22027792
- Journal Information:
- Applied Physics Letters, Vol. 99, Issue 18; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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