Spontaneous lateral composition modulation in InAlAs and InGaAs short-period superlattices
- Sandia National Labs., Albuquerque, NM (United States)
- National Renewable Energy Lab., Golden, CO (United States)
The microstructure of spontaneous lateral composition modulation along the [110] direction has been studied in (InAs){sub n}/(AlAs){sub m} short-period superlattices grown by molecular beam epitaxy on (001) InP. X-ray diffraction and transmission electron microscopy show that global strain ({var_epsilon}) in the superlattice reduces the degree of composition modulation, which disappears for the absolute value of {var_epsilon} > 0.7%. For tensile strains of {var_epsilon} {approx} +0.4%, they find that In-rich columns become regularly spaced and correlated with cusps in the growth surface. A similar correlation is seen in (InAs){sub n}/(GaAs){sub m} short-period superlattices between the enriched columns and the peaks and valleys of {l_brace}114{r_brace}{sub A} facets on the surface. The enriched columns in the (InAs){sub n}/(GaAs){sub m} layer (and the facets) extend for much longer distances ({approximately}0.2--0.4 {micro}m) in the [1{bar 1}0] direction than do the columns in the (InAs){sub n}/(AlAs){sub m} layer ({approximately} 56 nm).
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 515593
- Report Number(s):
- SAND--97-0738C; CONF-970782--3; ON: DE97007912
- Country of Publication:
- United States
- Language:
- English
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