Optical properties of spontaneous lateral composition modulation in AlAs/InAs short-period superlattices
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
The effect of lateral composition modulation, spontaneously generated during the epitaxial growth of an AlAs/InAs short-period superlattice, on the electronic band structure is investigated using phototransmission and photoluminescence spectroscopy. Compared with uniform layers of identical average composition, the presence of the composition modulation considerably reduces the band-gap energy and produces strongly polarized emission and absorption spectra. We demonstrate that the dominant polarization direction can selectively be aligned along the [1(bar sign)10] or [010] crystallographic directions. In compressively strained samples, the use of (001) InP substrates slightly miscut toward (111)A or (101) resulted in modulation directions along [110] or [100], respectively, and dominant polarization directions along a direction orthogonal to the respective composition modulation. Band-gap reductions as high as 350 and 310 meV are obtained for samples with composition modulation along [110] and [100], respectively. Ratios of polarized intensities up to 26 are observed in transmission spectra. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20217664
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 12 Vol. 77; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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