Interband transitions dependent on indium concentration in Ga1−xInxAs/GaAs asymmetric triple quantum wells

2018 ◽  
Vol 32 (05) ◽  
pp. 1850052 ◽  
Author(s):  
B. O. Alaydin ◽  
E. Ozturk ◽  
S. Elagoz
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electronic Properties ◽  
Radiative Decay ◽  
Interband Transition ◽  
Energy Levels ◽  
Oscillator Strengths ◽  
Quantum Well Structures ◽  
Transition Energies ◽  
Decay Times

In this paper, the optical and electronic properties of asymmetric triple quantum well (ATQW) structures are studied depending on the indium concentrations while quantum well (QW) thicknesses and barrier widths are kept constant. Calculation of electronic properties are done within the framework of the effective mass approximation. The indium concentrations in left quantum well (LQW) and right quantum well (RQW) are varied in order to see the change of energy levels. Then, interband transition energies, wavelengths, oscillator strengths and radiative decay times are determined depending on barrier height. The scope of this study, for the first time in the literature, covers converged interband transition energies for the asymmetric quantum well structures.

Optical evaluation of pretreated InGaN quantum well structures

2003 ◽  
Vol 798 ◽  
Author(s):  
T. Böttcher ◽  
F. Bertram ◽  
P. Bergman ◽  
A. Ueta ◽  
J. Christen ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Room Temperature ◽  
Growth Direction ◽  
Wetting Layer ◽  
Quantum Well Structures ◽  
Room Temperature Photoluminescence ◽  
Decay Times ◽  
Wavelength Distribution ◽  
Ingan Quantum Wells

ABSTRACTIn order to optimize the quantum efficiency of InGaN quantum wells, different MOVPE growth sequences are compared using photo- and electroluminescence. In one study, the surface was pretreated with trimethylindium (TMIn) prior to the well deposition. In another study, growth interruptions were performed after the quantum well deposition to desorb segregated indium. In both cases, the room-temperature photoluminescence (PL) intensity is strongly enhanced. For the samples grown with TMIn preflow the wavelength distribution in low-temperature cathodoluminescence (CL) wavelength mappings is narrowed, which can be attributed to more homogeneous quantum wells. Furthermore, the decay times of the radiative recombination increase both at RT and 2K. A reason for this could be an improved indium profile along the growth direction or a more homogeneous In wetting layer due to the pre-wetted surface.

Intra-magnetoexciton transitions in semiconductor quantum wells

2001 ◽  
Vol 692 ◽  
Author(s):  
Z. Barticevic ◽  
M. Pacheco ◽  
C. A. Duque ◽  
L. E. Oliveira
Keyword(s):  
Quantum Wells ◽  
Energy Levels ◽  
Far Infrared ◽  
Theoretical Work ◽  
Growth Direction ◽  
Oscillator Strengths ◽  
Transition Energies ◽  
Semiconductor Quantum Wells ◽  
Optically Detected ◽  
Optically Detected Resonance

AbstractHighly sensitive optically detected resonance experiments have shown that magnetoexcitons in GaAs-(Ga,Al)As semiconductor quantum wells have discrete internal energy levels, with transition energies found in the far-infrared (terahertz) region. Here we are concerned with a theoretical study of the terahertz transitions of light-hole and heavy-hole confined magnetoexcitons in GaAs-(Ga,Al)As quantum wells, under a magnetic field applied in the growth direction of the semiconductor heterostructure. The various magnetoexciton states are obtained in the effective-mass approximation by expanding the corresponding exciton-envelope wave functions in terms of appropriate Gaussian functions. The electron and hole cyclotron resonances and intra-magnetoexciton transitions are theoretically studied by exciting the allowed electron, hole and internal magnetoexcitonic transitions with far-infrared radiation. Theoretical results are obtained for both the intra-magnetoexciton transition energies and oscillator strengths associated with excitations from 1s - like to 2s, 2p±, and 3p±- like magnetoexciton states, and from 2p- to 2s – like exciton states. Present results are in overall agreement with available optically detected resonance measurements and clarifies a number of queries in previous theoretical work.

Recombination Dynamics in Nitride Quantum Boxes and Quantum Wells for Colors Ranging from the UV to the Red

2000 ◽  
Vol 639 ◽  
Author(s):  
P. Lefebvre ◽  
A. Morel ◽  
M. Gallart ◽  
T. Taliercio ◽  
B. Gil ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Room Temperature ◽  
Stokes Shift ◽  
Oscillator Strengths ◽  
Time Resolved ◽  
Transition Energies ◽  
Radiative Efficiency ◽  
Time Resolved Photoluminescence

ABSTRACTTime-resolved photoluminescence experiments at varying temperature are performed on a series of InxGa1−xN/GaN quantum well and quantum box samples of similar compositions (0.15 < x < 0.20). The results are analyzed by using envelope-function calculations of transition energies and oscillator strengths, accounting for internal electric fields. The respective influences of localization and electric fields on radiative and nonradiative lifetimes and on the Stokes shift are deduced. The results indicate that the spatial extension of localization centers is much smaller than the size of the quantum boxes (∼10 × 3 nm, typically). The room-temperature radiative efficiency of both quantum well and quantum box samples is enhanced by replacing the topmost GaN barrier by an AlGaN one.

Electronic Properties of Dislocations in Heavily Dislocated Quantum well Structures: Doping Effects

1989 ◽  
Vol 145 ◽  
Author(s):  
T. Y. Liu ◽  
P. M. Petroff ◽  
H. Kroemer ◽  
A. C. Gossard
Keyword(s):  
Low Temperature ◽  
Dislocation Density ◽  
Quantum Well ◽  
Quantum Wells ◽  
Electronic Properties ◽  
The Other ◽  
Quantum Well Structures ◽  
Luminescence Efficiency ◽  
Doping Effects ◽  
Multi Quantum Well

AbstractIn heavily dislocated GaAs (dislocation density of 108cm-2), the low-temperature cathodo- luminescence efficiency of quantum wells and superlattices is dramatically higher than that of a bulk-like layer. Furthermore, the luminescence efficiency can be further improved by doping the barriers of the GaAs/(Al,Ga)As multi-quantum well structures with beryllium (Be). Two quite different possible models for this observation are discussed: One assumes that the effect is due to the expulsion of dislocation kinks from the wells, the other that it is due to the effect of well width fluctuations.

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