Internal electric-field and segregation effects on luminescence properties of quantum wells

2005 ◽  
Vol 98 (2) ◽  
pp. 023501 ◽  
Author(s):  
G. Gonzalez de la Cruz ◽  
A. Calderon Arenas ◽  
H. Herrera
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Luminescence Properties ◽  
Internal Electric Field

Barrier composition dependence of the internal electric field in ZnO∕Zn1−xMgxO quantum wells

2007 ◽  
Vol 90 (20) ◽  
pp. 201912 ◽  
Author(s):  
T. Bretagnon ◽  
P. Lefebvre ◽  
T. Guillet ◽  
T. Taliercio ◽  
B. Gil ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Composition Dependence ◽  
Internal Electric Field

Electron capture by quantum wells in an internal electric field

2004 ◽  
Vol 95 (8) ◽  
pp. 4204-4208 ◽  
Author(s):  
L. Villegas-Lelovsky ◽  
G. González de la Cruz
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Electron Capture ◽  
Internal Electric Field

scholarly journals Optical Measurements and Theoretical Modelling of Excitons in Double ZnO/ZnMgO Quantum Wells in an Internal Electric Field

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7222
Author(s):  
Janusz Andrzejewski ◽  
Mieczyslaw Antoni Pietrzyk ◽  
Dawid Jarosz ◽  
Adrian Kozanecki
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Optical Measurements ◽  
Theoretical Modelling ◽  
Linear Potential ◽  
Internal Electric Field ◽  
Photoluminescence Spectra ◽  
Consistent Model ◽  
Asymmetric Quantum ◽  
Different Thickness

In this paper, the photoluminescence spectra of excitons in ZnO/ZnMgO/ZnO double asymmetric quantum wells grown on a–plane Al2O3 substrates with internal electric-field bands structures were studied. In these structures, the electron and the hole in the exciton are spatially separated between neighbouring quantum wells, by a ZnMgO barrier with different thickness. The existence of an internal electric field generates a linear potential and, as a result, lowers the energy of quantum states in the well. For the wide wells, the electrons are spatially separated from the holes and can create indirect exciton. To help the understanding of the photoluminescence spectra, for single particle states the 8 k·p for wurtzite structure is employed. Using these states, the exciton in the self-consistent model with 2D hydrogenic 1s–like wave function is calculated.

Using graded barriers to control the optical properties of ZnO/Zn0.7Mg0.3O quantum wells with an intrinsic internal electric field

2010 ◽  
Vol 96 (19) ◽  
pp. 193117 ◽  
Author(s):  
C. R. Hall ◽  
L. V. Dao ◽  
K. Koike ◽  
S. Sasa ◽  
H. H. Tan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
Quantum Wells ◽  
Internal Electric Field

Cathodoluminescence depth-profiling studies of GaN/AlGaN quantum-well structures

2000 ◽  
Vol 15 (2) ◽  
pp. 495-501 ◽  
Author(s):  
M. Godlewski ◽  
E. M. Goldys ◽  
M. R. Phillips ◽  
R. Langer ◽  
A. Barski
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Piezoelectric Effect ◽  
Depth Profiling ◽  
Yellow Emission ◽  
Internal Electric Field ◽  
Edge Emission ◽  
Quantum Well Structures ◽  
Accumulation Of Defects

In this paper we evaluate the in-depth homogeneity of GaN epilayers and the influence of electric field present in strained GaN/AlGaN heterostructures and quantum wells on the yellow and “edge” emission in GaN and AlGaN. Our depth-profiling cathodoluminescence measurements show an increased accumulation of defects at the interface. Inhomogeneities in the doping level are reflected by the enhancement of the yellow emission in the interface region. The piezoelectric effect is found to strongly reduce the emission from the strained AlGaN quantum-well barriers. We also show that Ga droplets, commonly found on surfaces of samples grown in Ga-rich conditions, screen the internal electric field in a structure and thus result in a local enhancement of the edge emission intensity.

Nonlinear optical properties in the laser-dressed two-level AlxGa1−xN/GaN single quantum well

2018 ◽  
Vol 32 (04) ◽  
pp. 1850032 ◽  
Author(s):  
Monalisa Panda ◽  
Tapaswini Das ◽  
B. K. Panda
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Effective Mass ◽  
Nonlinear Optical ◽  
Energy Levels ◽  
Internal Electric Field ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Increase With Increase

The electronic states in the laser-dressed hexagonal and cubic Al[Formula: see text]Ga[Formula: see text]N/GaN single quantum wells are calculated using the effective mass equation. The hexagonal single quantum well contains an internal electric field due to spontaneous and piezoelectric polarizations. The effective mass equation is solved by the finite difference method. The energy levels in both cubic and hexagonal laser-dressed wells are found to increase with increase in laser dressing as the effective well widths in both the wells increase. The intersubband energy spacing between first excited state and ground state increases in the cubic quantum well, whereas it decreases in the hexagonal well due to the presence of internal electric field in it. Using the compact density matrix method with iterative procedure, first-, second- and third-order nonlinear optical susceptibilities in the laser-dressed quantum well are calculated taking only two levels. While the susceptibilities in the hexagonal well are found to get red shifted, the susceptibilities in the cubic well are blue shifted.

Group-III Nitride Quantum Heterostructures Emitting in the whole Visible Range

2000 ◽  
Vol 639 ◽  
Author(s):  
Nicolas Grandjean ◽  
Benjamin Damilano ◽  
Jean Massies
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Stark Effect ◽  
Radiative Lifetime ◽  
Visible Spectrum ◽  
Visible Range ◽  
Internal Electric Field ◽  
Carrier Localization ◽  
Group Iii ◽  
Group Iii Nitride

ABSTRACTGroup-III nitride quantum wells (QWs) and quantum dots (QDs) have been grown by molecular beam epitaxy (MBE). Their optical properties are shown to be governed by the presence of a huge internal polarization field. For example, GaN/AlN QDs emit from the blue to the orange due to the giant quantum confined Stark effect (QCSE) induced by a built- in electric field of 4 MV/cm. Another consequence of the QCSE is to drastically reduces the oscillator strength of the ground state transition and thereby to increase by several orders of magnitude its radiative lifetime. Despite the very large density of dislocations in nitride layers, which induce non-radiative recombinations, carrier localization enhances the photoluminescence (PL) efficiency. This is demonstrated by GaN/AlN QDs grown on silicon substrates exhibiting strong PL intensity at room temperature. InGaN/GaN QWs with In composition of 20% also display 300 K PL peaking through the whole visible spectrum (0.4-0.66 νm). This is achieved by varying the QW thickness from 1.5 to 5.5 nm, the red-shift resulting from an internal electric field of 2.5 MV/cm. For InGaN/GaN QWs emitting at 2.8-2.9 eV, the PL efficiency at 300 K is larger than 10 %. This is ascribed to carrier localization, which is not due to InGaN phase separation that would form QDs, as revealed by transmission electron microscopy. Another origin of the carrier localization in InGaN/GaN QWs is then discussed.

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