Excitation of optical transitions in the InxGa1−xAs‐GaAs quantum well system by the free exciton in the barrier

1993 ◽  
Vol 74 (2) ◽  
pp. 1453-1455 ◽  
Author(s):  
D. C. Reynolds ◽  
B. Jogai ◽  
P. W. Yu ◽  
C. E. Stutz
Keyword(s):  
Quantum Well ◽  
Free Exciton ◽  
Optical Transitions

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.

Temperature dependence of optical transitions in AlxGa1–xAs/GaAs quantum well structures grown by molecular beam epitaxy

2005 ◽  
Vol 490 (2) ◽  
pp. 161-164 ◽  
Author(s):  
A. Caballero-Rosas ◽  
C. Mejía-García ◽  
G. Contreras-Puente ◽  
M. López-López
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Well ◽  
Temperature Dependence ◽  
Molecular Beam ◽  
Optical Transitions ◽  
Quantum Well Structures

The effect of hydrostatic pressure on subband structure and optical transitions in modulation-doped quantum well

2011 ◽  
Vol 49 (6) ◽  
pp. 635-643 ◽  
Author(s):  
F. Ungan ◽  
U. Yesilgul ◽  
S. Sakiroglu ◽  
E. Kasapoglu ◽  
H. Sari ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Quantum Well ◽  
Optical Transitions ◽  
Effect Of Hydrostatic Pressure ◽  
Subband Structure

Free exciton versus free carrier luminescence in a quantum well

1993 ◽  
Vol 03 (C5) ◽  
pp. 11-14 ◽  
Author(s):  
B. DEVEAUD ◽  
B. SERMAGE ◽  
D. S. KATZER
Keyword(s):  
Quantum Well ◽  
Free Exciton ◽  
Free Carrier

Comparison of optical transitions in InGaN quantum well structures and microdisks

2001 ◽  
Vol 89 (9) ◽  
pp. 4951-4954 ◽  
Author(s):  
Lun Dai ◽  
Bei Zhang ◽  
J. Y. Lin ◽  
H. X. Jiang
Keyword(s):  
Quantum Well ◽  
Optical Transitions ◽  
Quantum Well Structures

scholarly journals Dependence of InGaN Quantum Well Thickness on the Nature of Optical Transitions in LEDs

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 237
Author(s):  
Mateusz Hajdel ◽  
Mikolaj Chlipała ◽  
Marcin Siekacz ◽  
Henryk Turski ◽  
Paweł Wolny ◽  
...  
Keyword(s):  
Quantum Well ◽  
Emission Spectra ◽  
Spatial Separation ◽  
Blue Shift ◽  
Electroluminescence Spectrum ◽  
Complex Spectrum ◽  
Optical Transitions ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Current Densities

The design of the active region is one of the most crucial problems to address in light emitting devices (LEDs) based on III-nitride, due to the spatial separation of carriers by the built-in polarization. Here, we studied radiative transitions in InGaN-based LEDs with various quantum well (QW) thicknesses—2.6, 6.5, 7.8, 12, and 15 nm. In the case of the thinnest QW, we observed a typical effect of screening of the built-in field manifested with a blue shift of the electroluminescence spectrum at high current densities, whereas the LEDs with 6.5 and 7.8 nm QWs exhibited extremely high blue shift at low current densities accompanied by complex spectrum with multiple optical transitions. On the other hand, LEDs with the thickest QWs showed a stable, single-peak emission throughout the whole current density range. In order to obtain insight into the physical mechanisms behind this complex behavior, we performed self-consistent Schrodinger–Poisson simulations. We show that variation in the emission spectra between the samples is related to changes in the carrier density and differences in the magnitude of screening of the built-in field inside QWs. Moreover, we show that the excited states play a major role in carrier recombination for all QWs, apart from the thinnest one.

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