Ultrathin GaAs layers embedded in AlAs: The observation of intense short-wavelength emission

Type-II GaAs/AlAs multiple-quantum well samples groan by low-pressure metal-organic vapour-phase epitaxy have been investigated. The layered structures consist of 50 periods of either 2 monolayers (ML), 4 ML. 5 ML, 6 ML, or 7 ML GaAs embedded in 28 ML AlAs. Using (100) GaAs substrates 6 degrees misoriented towards the nearest (111)B plane monolayer steps at the AlAs/GaAs/AlAs interfaces with regular terrace widths (2.7 nm) can be seen by high-resolution transmission electron microscopy. In the photoluminescence spectra even at room temperature type-I luminescence is found to be dominant. The peak wavelength of this emission ranges from 620 to 440 nm and is governed by the GaAs layer thickness. The comparison of the measured transition energies with calculations based on an effective mass approach and an empirical tight-binding Green's function scheme shows good agreement. The perfect interface structure of our samples with regular distribution of monolayer steps prevents obviously the loss of photoexcited carriers from the GaAs layers to the surrounding, energetically resonant AlAs material allowing only low type-II luminescence intensity. Furthermore, for our well thicknesses 2D phonons have to be coupled with 3D electrons leading to low electron-phonon interaction.


Published in:
Physica Status Solidi a-Applied Research, 164, 1, 165-168
Year:
1997
ISSN:
0031-8965
Note:
Univ Leipzig, Fac Phys, D-04103 Leipzig, Germany. Univ Leipzig, Fac Chem, D-04103 Leipzig, Germany. PHB Ecublens, Swiss Fed Inst Technol Lausanne, Dept Phys, CH-1015 Lausanne, Switzerland. Schwabe, R, Univ Leipzig, Fac Phys, Linnestr 3-5, D-04103 Leipzig, Germany. schwabe@server1.rz.uni-leipzig.de
ISI Document Delivery No.: YP830
Times Cited: 1
Cited Reference Count: 8
Cited References:
ANDREANI LC, 1997, P MODULATED SEMICOND
DIVENTRA M, 1997, PHYS REV B, V55, P13148
MADER KA, 1992, P INT M OPT EXC CONF, P341
MADER KA, 1992, THESIS SWISS FEDERAL
MASCHKE K, 1991, PHYS REV LETT, V67, P2646
MEYNADIER MH, 1988, PHYS REV LETT, V60, P1338
MOORE KJ, 1989, SPECTROSCOPY SEMICON, P293
SCHWABE R, 1997, PHYS REV B, V56, R4329
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 Record created 2007-08-31, last modified 2018-03-17


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