Modulated Reflectance Spectroscopy of CdTe-Cd1−xMnxTe Multiple Quantum Wells and Superlattices Grown by Pulsed Laser Evaporation and Epitaxy

1992 ◽  
Vol 285 ◽  
Author(s):  
D. Labrie ◽  
J.J. Dubowski
Keyword(s):  
Quantum Wells ◽  
Heavy Hole ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Pulsed Laser ◽  
Reflectance Spectroscopy ◽  
Light Hole ◽  
Laser Evaporation ◽  
Multiple Quantum ◽  
Superlattice Structures

ABSTRACTPiezoreflectance and photoreflectance spectroscopies have been used to investigate the electronic properties of CdTe-Cd1-xMnxTe (x − 0.10) multiple quantum well and superlattice structures grown by Pulsed Laser Evaporation and Epitaxy (PLEE). The structures with the CdTe well widths from 54Å to 245Å have been investigated. The spectra exhibit a series of signatures which are attributed to free exciton transitions occuring between the heavy-hole and light-hole bands and the upper electron subbands within the CdTe well layers. The spectra indicate that the PLEE grown structures are of an excellent quality typical of the best currently available material.

Excited quantum states in CdTe–Cd1−x MnxTe multiple quantum wells and superlattices grown by pulsed laser evaporation and epitaxy

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1027-1034 ◽  
Author(s):  
D. Labrie ◽  
X. Wang ◽  
J. J. Dubowski
Keyword(s):  
Quantum Wells ◽  
Heavy Hole ◽  
Free Exciton ◽  
Pulsed Laser ◽  
Light Hole ◽  
Multiple Quantum Wells ◽  
Laser Evaporation ◽  
Multiple Quantum ◽  
Transition Energies ◽  
Line Positions

The photoreflectance and piezoreflectance spectra of CdTe–Cd0.9Mn0.1 Te multiple quantum wells and superlattices grown by pulsed laser evaporation and epitaxy display series of signatures that are attributed to free exciton transitions occurring between the heavy-hole and light-hole bands, and the upper electron subbands. The signature line positions are in excellent agreement with calculated transition energies obtained from a simple Kronig–Penney model that includes strain effects and the nonparabolicity of the conduction band.

PHOTOCONDUCTIVITY, PHOTOREFLECTANCE AND PHOTOLUMINESCENCE OF GaAs-AlAs MULTIPLE QUANTUM WELLS

1985 ◽  
Vol 56 ◽  
Author(s):  
H. NEFF ◽  
K. J. BACHMANN ◽  
W. D. LAIDIG
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Heavy Hole ◽  
Multiple Quantum Well ◽  
Light Hole ◽  
Multiple Quantum ◽  
Indirect Transition ◽  
Temperature Dependent ◽  
Direct Inter ◽  
Phonon Absorption

AbstractEmploying temperature dependent photoconductivity, photoluminescence and photoreflectivity measurements, we have analyzed a GaAs-AlAs multiple quantum well. The above optical techniques clearly resolve the fundamental inter-subband transitions, including heavy hole-light hole splittings. At T < 60K an anomalously high photoconductivity was discovered below the direct inter-subband transitions and is attributed tentatively to the presence of extrinsic interface states within the bandgap. For T > l00K the fundamental indirect transition was discovered and associated with LO (L) - phonon absorption.

Optical properties of CdTe-Cd0.90Mn0.10Te multiple quantum well structures grown by pulsed laser evaporation and epitaxy

1992 ◽  
Vol 117 (1-4) ◽  
pp. 862-866 ◽  
Author(s):  
J.J. Dubowski ◽  
A.P. Roth ◽  
E. Deleporte ◽  
G. Peter ◽  
Z.C. Feng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Well ◽  
Multiple Quantum Well ◽  
Pulsed Laser ◽  
Laser Evaporation ◽  
Multiple Quantum ◽  
Quantum Well Structures

scholarly journals Photo- and cathodoluminescence investigations of piezoelectric GaN/AlGaN quantum wells

2000 ◽  
Vol 639 ◽  
Author(s):  
E.M. Goldys ◽  
M. Godlewski ◽  
M.R. Phillips ◽  
A.A. Toropov
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Depth Profiling ◽  
Multiple Quantum ◽  
Recombination Mechanism ◽  
Decay Times ◽  
Piezoelectric Fields

ABSTRACTWe have examined multiple quantum well AlGaN/GaN structures with several quantum wells of varying widths. The structures had strain-free quantum wells and strained barriers. Strong piezoelectric fields in these structures led to a large red shift of the PL emission energies and long decay times were also observed. While the peak energies could be modelled using the effective mass approximation, the calculated free exciton radiative lifetimes were much shorter than those observed in experiments, indicating an alternative recombination mechanism, tentatively attributed to localised excitons. Cathodoluminescence depth profiling revealed an unusually small penetration range of electrons suggesting that electron-hole pairs preferentially remain within the multiple quantum well region due to the existing electric fields. Spatial fluctuations of the cathodoluminescence intensity were also observed.

Light- and Heavy-Hole Bound Exciton Transitions and Free to Bound Transitions in GaxAl1-xAs/GaAs Quantum Wells

1989 ◽  
Vol 163 ◽  
Author(s):  
Donald C. Reynolds ◽  
K.K. Bajaj
Keyword(s):  
Quantum Wells ◽  
Heavy Hole ◽  
Free Exciton ◽  
Light Hole ◽  
Binding Energies ◽  
Temperature Dependent ◽  
Neutral Donor ◽  
Free Hole ◽  
Quantum Well Structures ◽  
Exciton Transitions

AbstractExcitons bound to neutral donors in AlxGa1-xAs/GaAs quantum wells were observed by high resolution resonant excitation photoluminescence, and temperature dependent photoluminescence measurements. Changes in the binding energy of excitons are observed when the donors are located in the center of the well, at the edge of the well, or in the center of the barrier. The variations in these binding energies are reported as a function of well size from 75–350Å. The binding energies increased as the well size was reduced to about 100Å, with further reductions in well size they decreased.Light-hole free excitons bound to neutral donors were observed in AlxGa1-xAs/GaAs quantum wells. The transitions were observed, using selective excitation photoluminescence spectroscopy, in the energy region between the light-hole and heavy-hole free exciton transitions where no other intrinsic transitions exist. The neutral donor-bound heavy-hole free-exciton transitions were also observed when the light-hole bound exciton transitions were observed. Quantum well structures which showed no evidence of a heavy-hole donor bound exciton also showed no evidence of a light-hole donor bound exciton.Free to bound transitions, free hole to bound electron, have also been observed in the AlxGa1-xAs/GaAs quantum wells. The diamagnetic shift of these transitions was used to distinguish them from excitonic transitions.

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