Resonant Photoluminescence Excitation in GaAs Grown Directly on Si

1988 ◽  
Vol 116 ◽  
Author(s):  
S. Zemon ◽  
C. Jagannath ◽  
S. K. Shastry ◽  
W. J. Miniscalco ◽  
G. Lambert

AbstractWe describe new results observed during resonant excitation in the excitonic region of GaAs grown directly on Si by organometallic vapor phase epitaxy. Two resolved features were found in the light hole photoluminescence (PL) region, one identified with a free exciton process and the other with donor-related transitions. Features which track the laser excitation line were observed and identified with a process in which a donor is excited from the n=l ground state to an n=2 excited state. The PL excitation spectra associated with these features have spectral widths as narrow as 1.5 meV. PL spectral widths of ~3 meV have been attained for the heavy hole exciton band, representing the narrowest value obtained for OMVPE material and an improvement of about 30% over our best previous results.

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Takuya Kawazu

Optical properties of GaAs/AlGaAs quantum wells (QWs) in the vicinity of InAlAs quantum dots (QDs) were studied and compared with a theoretical model to clarify how the QD strain affects the electronic states in the nearby QW. In0.4Al0.6As QDs are embedded at the top of the QWs; the QD layer acts as a source of strain as well as an energy barrier. Photoluminescence excitation (PLE) measurements showed that the QD formation leads to the increase in the ratio Ie-lh/Ie-hh of the PLE intensities for the light hole (lh) and the heavy hole (hh), indicating the presence of the valence band mixing. We also theoretically calculated the hh-lh mixing in the QW due to the nearby QD strain and evaluated the PLE ratio Ie-lh/Ie-hh.


1987 ◽  
Vol 91 ◽  
Author(s):  
C. Jagannath ◽  
S. Zemon ◽  
P. Norris ◽  
B.S. Elman ◽  
S.K. Shastry

ABSTRACTPhotoluminescence and photoluminescence excitation spectroscopies are utilized to study excitons in GaAs/AlGaAs quantum wells (QW's) fabricated using MBE on MOCVD grown GaAs/Si. The experimental results are understood in terms of the biaxial tension of approximately 3 kbar present in the plane of growth for both the QW's and the GaAs buffer. An important consequence of the biaxial tension is that for QW's with well widths larger than ≈15 nm the light- and heavy- hole sub-bands cross each other in energy. This results in the light-hole exciton energy being lower than that of the heavy-hole exciton, opposite to the case of QW's grown on GaAs substrates.


1989 ◽  
Vol 163 ◽  
Author(s):  
Donald C. Reynolds ◽  
K.K. Bajaj

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.


1981 ◽  
Vol 59 (2) ◽  
pp. 266-270 ◽  
Author(s):  
W. H. Hocking ◽  
A. J. Merer ◽  
D. J. Milton

New grating and laser excitation spectra of VO show resolved nuclear hyperfine structure in the lines of the F1 and F4 electron spin components in the C4Σ−–X4Σ−electronic transition. It is shown that the C4Σ− state has a sizeable hyperfine structure, with the Fermi contact parameter bF (the coefficient of I∙S in the magnetic hyperfine Hamiltonian) equal to −0.00773 cm−1. Another internal hyperfine perturbation, of the type described by Richards and Barrow for the ground state, occurs in the C4Σ−state near N = 5; the line doublings are consistent with the Fermi contact parameter derived from the F1 and F4 lines.


1992 ◽  
Vol 285 ◽  
Author(s):  
D. Labrie ◽  
J.J. Dubowski

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.


1996 ◽  
Vol 449 ◽  
Author(s):  
D. Kovalev ◽  
B. Averboukh ◽  
B. K. Meyer ◽  
D. Volm ◽  
H. Amano ◽  
...  

ABSTRACTWe present a detailed photoluminescence excitation study of the optical transitions in GaN. This technique is employed to distinguish between band-to-band excitation and exciton contribution to the formation of the free exciton, bound exciton, violet and yellow photoluminescence bands. We show the dominant role of the Fröhlich polar intraband scattering in the formation of the free exciton states. We demonstrate that bound exciton states in a large extent are created by the capture of the free excitons by shallow impurities as well as by phononassisted resonant excitation of the bound exciton states. The capture of the free carriers excited in the band continuum is a main excitation source for the violet and yellow bands. However, distinct A- and C-exciton resonances are detected in the excitation spectra of the violet and yellow emission bands.


1992 ◽  
Vol 61 (26) ◽  
pp. 3169-3171 ◽  
Author(s):  
G. W. ’t Hooft ◽  
C. J. B. Riviere ◽  
M. P. C. M. Krijn ◽  
C. T. H. F. Liedenbaum ◽  
A. Valster

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1027-1034 ◽  
Author(s):  
D. Labrie ◽  
X. Wang ◽  
J. J. Dubowski

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.


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