Free-standing versus AlAs-embedded GaAs quantum dots, wires, and films: The emergence of a zero-confinement state
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
Using a plane-wave pseudopotential method we investigate the electronic structure of free-standing and of AlAs-embedded GaAs quantum dots, wires, and films. We predict that (i) the confinement energy of the valence-band maximum (VBM) is larger in AlAs-embedded than in free-standing quantum structures, because of the zero-confinement character of the VBM wave function in the latter case; (ii) small GaAs quantum structures have an indirect band gap, whereas large GaAs quantum structures have a direct band gap; (iii) the conduction-band minimum of small free-standing quantum structures originates from the GaAs {ital X}{sub 1{ital c}} valley, while it derives from the AlAs {ital X}{sub 1{ital c}} state in AlAs-embedded quantum structures; (iv) the critical size for the direct/indirect crossover is larger in embedded quantum structures than in free-standing quantum structures. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- National Renewable Energy Laboratory
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 284636
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 24 Vol. 68; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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