Luminescence Studies of MBE Grown SI/SIGE Quantum Wells

1993 ◽  
Vol 298 ◽  
Author(s):  
M. Gail ◽  
J. Brunner ◽  
U. Menczigar ◽  
A. Zrenner ◽  
G. Abstreiter
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Elevated Temperatures ◽  
Variational Calculation ◽  
Exciton Binding Energy ◽  
Quantum Well Structures ◽  
Mass Approximation ◽  
Wide Range ◽  
Good Agreement

AbstractWe report on detailed luminescence studies of MBE grown Si/Si1-xGex quantum well structures. Both well width and composition is varied over a wide range. Bandgap photoluminescence is observed for all samples grown at elevated temperatures. The measured bandgap energies are in good agreement with subband calculations based on effective mass approximation and taking into account the segregation of Ge atoms during growth. Diffusion is found to limit quantum well (QW) growth with Ge-contents above 35% at high temperatures. The photoluminescence signals are detected up to about 100K and can be attributed to interband transitions of free excitons. We also present investigations of the exciton binding energy as a function of well width and composition. The observed shift of the exciton binding energy is compared with results of a variational calculation. A distinct onset in photocurrent and electroluminescence up to 200 K are observed in quantum well diodes.

LOCALIZED EXCITONS IN SELF-ASSEMBLED InxGa1-xN QUANTUM DOTS

2005 ◽  
Vol 19 (12) ◽  
pp. 589-598
Author(s):  
XIAN-QI DAI ◽  
FENG-ZHEN HUANG ◽  
JUN-JIE SHI
Keyword(s):  
Quantum Dots ◽  
Binding Energy ◽  
Variational Approach ◽  
Structural Parameters ◽  
Exciton Binding Energy ◽  
Mass Approximation ◽  
Energy Maximum ◽  
Localized Excitons ◽  
The Relationship ◽  
Good Agreement

Within the framework of effective-mass approximation, the exciton states localized in cylindrical InGaN quantum dots (QDs) are investigated using a variational approach. The relationship between the exciton states and structural parameters of QDs with radius R and height L are studied in detail. The numerical results show that the exciton binding energy is sensitive to the ratio of R/L for a QD with a given volume. There is a maximum in the binding energy, where the electrons and holes are the most efficiently confined in the QDs with special structural parameters. The binding energy maximum can be obtained at about L = 1.7 nm for different QD volumes. The exciton binding energy and emission wavelength depend sensitively on structural parameters and the In content in the In x Ga 1-x N active layer. Our calculated emission wavelengths are in good agreement with experimental data.

SHALLOW DONORS IN A COUPLED TRIPLE GRADED QUANTUM WELL UNDER THE ELECTRIC AND MAGNETIC FIELDS

2006 ◽  
Vol 13 (04) ◽  
pp. 397-401 ◽  
Author(s):  
E. KASAPOGLU ◽  
H. SARI ◽  
I. SÖKMEN
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Growth Direction ◽  
Physical Parameters ◽  
Donor Impurity ◽  
Quantum Well Structures ◽  
Hydrogenic Donor Impurity ◽  
Electric And Magnetic Fields

The binding energy of the donor in three different shaped triple graded GaAs -( Ga , Al ) As quantum wells which is obtained by changing the depth of the central-well potential (Vo) is calculated by using a variational approach. The results have been obtained in the presence of uniform magnetic and electric fields applied along the growth direction as a function of the impurity position. In addition, we also give the binding energy of the hydrogenic donor impurity for triple square quantum wells having the same physical parameters with triple graded quantum well structures in order to see the effect of different geometric confinements on the donor impurity binding energy.

scholarly journals Спектр двойных акцепторов в слоях барьеров и квантовых ям   гетероструктур HgTe/СdHgTe

2019 ◽  
Vol 53 (9) ◽  
pp. 1224
Author(s):  
Д.В. Козлов ◽  
В.В. Румянцев ◽  
С.В. Морозов
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Photoluminescence Spectrum ◽  
Spectral Features ◽  
Image Charge ◽  
Charge Potential ◽  
Induced Charge ◽  
Mercury Vacancies ◽  
Good Agreement

AbstractThe states of double acceptors in HgTe/СdHgTe heterostructures containing quantum wells are theoretically investigated taking into account the substantial difference in the values of the permittivities of the barrier and quantum-well layers. The effect of such a difference and the charge induced at the heterointerfaces arising from it are described with the image-charge potential. Calculation shows a significant change in the binding energy of the acceptor centers—mercury vacancies due to the induced charge; the ionization energies of mercury vacancies are in good agreement with the position of the spectral features in the photoluminescence spectrum of the HgTe/CdHgTe heterostructures containing quantum wells.

X-Ray Scattering (Modeling and Experiment) of InxGa1-xAs/GaAs Multiple Quantum Wells

1987 ◽  
Vol 103 ◽  
Author(s):  
Jichai Jeong ◽  
J. C. Lee ◽  
M. A. Shahid ◽  
T. E. Schlesinger ◽  
A. G. Milnes
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Quantum Well Structures ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Good Agreement

ABSTRACTX-ray diffraction, transmission electron microscopy (TEM), and photoluminescence measurements have been made on strained InxGa1-xAs/GaAs quantum well structures. The well widths measured from TEM are 187, 115 and 69 Å for an interrupted growth, and 218, 126, 60 Å for a non-interrupted growth. In the measured x-ray diffraction patterns, the Pendellosung fringes due to GaAs barriers are modulated by a broad weak peak mostly coming from the thickest InxGa1-xAs well layer and is fairly symmetric for the noninterrupted sample. For the interrupted quantum well, the x-ray diffraction pattern is less symmetric, since there is further modulation by another broader and weaker peak. This results show that the In content in the InxGa1-xAs well layers are not well controlled for the interrupted quantum well. Using actual thickness measured from TEM, x-ray diffraction patterns are calculated and good agreement is obtained between the measured and the calculated x-ray diffraction patterns. The three strained InxGa1-xAs/Gaks quantum wells grown without interruption produce high intensity and narrow full-width at half-maximum (FWHIM) of 2.9 meV of the photoluminescence peak. The photoluminescence peaks for the interrupted quantum well are relatively broad and asymmetric, and have lower intensities, indicating that better quality InxGa1-xAs/GaAs quantum wells can be grown without interruption.

Simultaneous effects of pressure and temperature on excitons in Pöschl–Teller quantum well

2017 ◽  
Vol 31 (08) ◽  
pp. 1750050 ◽  
Author(s):  
A. Anitha ◽  
M. Arulmozhi
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Effective Mass ◽  
Heavy Hole ◽  
Light Hole ◽  
Binding Energies ◽  
Exciton Binding Energy ◽  
Effective Mass Approximation ◽  
Mass Approximation ◽  
Asymmetric Configuration

Binding energies of the heavy hole and light hole exciton in a quantum well with Pöschl–Teller (PT) potential composed of GaAs have been studied variationally within effective mass approximation. The effects of pressure and temperature on exciton binding energy are analyzed individually and also simultaneously for symmetric and asymmetric configuration of the well. The results show that exciton binding energy (i) decreases as the well width increases, (ii) increases with pressure and (iii) decreases with temperature. Simultaneous effects of these perturbations lead to more binding of the exciton. The results are compared with the existing literature.

OMVPE Growth of GalnAs/InP Quantum Well Structures

1987 ◽  
Vol 102 ◽  
Author(s):  
G. B. Stringfellow
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Quantum Wells ◽  
Vapor Phase ◽  
Atmospheric Pressure ◽  
Growth Conditions ◽  
Binding Energies ◽  
Optimum Conditions ◽  
Quantum Well Structures ◽  
Maximum Value

ABSTRACTInP/GalnAs/InP quantum well structures have been grown using atmospheric pressure organometallic vapor phase epitaxy (AP-OMVPE). The optimum conditions for growth of extremely abrupt interfaces were studied. The optimum orientation was exactly (100). The growth had to be interrupted for 40 seconds at the first interface and 2 minutes at the 2nd interface to obtain the most abrupt interfaces. The narrowest photoluminescence half widths were obtained at the lowest values (31) of V/III ratio in the input vapor phase. These growth conditions allow the growth of wells as thin as <10Å with photoluminescence (PL) spectra consisting of doublets or triplets. The extremely narrow peaks correspond to regions of the quantum well differing in thickness by a single monolayer. The energy separations of the neighboring peaks are found to increase with decreasing well width until, at a thickness of approximately 12 Å, the separation begins to decrease rapidly with decreasing well width. The exciton binding energies in the quantum wells have also been measured using thermally modulated PL. The binding energy is found to increase with decreasing well width until a maximum value of approximately 17 meV is measured for a nominal well width of approximately 13 Å. For thinner wells the exciton binding energy is found to decrease with decreasing well width.

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