Binding Energies of Excitons in GaAs/AlAs Quantum Wells Under Pressure

2003 ◽  
Vol 17 (16) ◽  
pp. 863-870 ◽  
Author(s):  
Guojun Zhao ◽  
X. X. Liang ◽  
S. L. Ban

The binding energy of an exciton in the GaAs/AlAs quantum well is discussed including the influence of interface optical phonons and bulk longitudinal optical phonons confined in the well under hydrostatic pressure. The dependence of the phonon energies on pressure is considered using a linear interpolation method to obtain the pressure effect on the exciton binding energy by a variational calculation. The result shows that the polaronic effect on the exciton binding energies cannot be neglected and the pressure effect on the exciton-phonon interaction is obvious.

2003 ◽  
Vol 17 (17) ◽  
pp. 909-919 ◽  
Author(s):  
Y. L. Cao ◽  
S. L. Ban ◽  
G. J. Zhao

A variational method is used to investigate the binding energies of bound polarons near the interface in a GaAs/Al x Ga 1-x As heterojunction by considering the hydrostatic pressure effect. It is found that the comprehensive pressure effect on the heterojunction factors increases the binding energies near linearly. The pressure influence on the binding energy for the impurity located on the channel side is stronger than that for the impurity located on the barrier side. The pressure effect is more obvious when the impurity is located on the channel side and is not so far from the interface. The pressure influences on the longitudinal optical phonons and interface optical phonons are discussed.


2004 ◽  
Vol 18 (22) ◽  
pp. 2991-2999 ◽  
Author(s):  
FENG-QI ZHAO ◽  
ZI-ZHENG GUO

The free polaron energy levels in finite GaAs / Al x Ga 1-x As parabolic quantum wells have been investigated by a modified variational method. The effect of the electric field, the electron-phonon interaction including the longitudinal optical phonons and the four branches of interface optical phonons, and the effect of spatial dependent effective mass have been considered in the calculation. The dependence of the energies of free polarons on the alloy composition x is given. The numerical results for finite GaAs / Al x Ga 1-x As parabolic quantum wells are obtained and discussed. The results show that the effect of the electric field and the interface optical phonons as well as the longitudinal optical phonons on the energy levels is obvious. One can find that the effect of the spatially dependent effective masses on the energy levels in finite parabolic quantum wells is considerable except for large well width. Thus, the electron-phonon interaction and the effect of the spatially dependent effective mass should not be neglected for the study of the electron state problem in finite parabolic quantum wells.


Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина

Abstract The specific features of the interaction of charged particles with polar optical phonons have been studied theoretically for quantum wells with the barriers that are asymmetric in their dielectric properties. It is shown that the interaction with interface phonon modes makes the greatest contribution in narrow quantum wells. The parameters of the electron-phonon interaction were found for the cases of different values of the phonon frequencies in the barrier materials. It turned out that a significant (by almost an order of magnitude) change in the parameters of the electron-phonon interaction can occur in such structures. This makes it possible, in principle, to trace the transition from weak to strong interactions in quantum wells of the same type but with different compositions of barrier materials. The conditions are found under which an enhancement of the electron-phonon interaction is possible in an asymmetric structure in comparison with a symmetric one with the barriers of the same composition.


1987 ◽  
Vol 35 (11) ◽  
pp. 5925-5928 ◽  
Author(s):  
M. S. Skolnick ◽  
K. J. Nash ◽  
P. R. Tapster ◽  
D. J. Mowbray ◽  
S. J. Bass ◽  
...  

2016 ◽  
Vol 30 (24) ◽  
pp. 1630006 ◽  
Author(s):  
I. V. Bondarev

A configuration space method is developed for binding energy calculations of the lowest energy exciton complexes (trion, biexciton) in spatially confined quasi-1D semiconductor nanostructures such as nanowires and nanotubes. Quite generally, trions are shown to have greater binding energy in strongly confined structures with small reduced electron–hole masses. Biexcitons have greater binding energy in less confined structures with large reduced electron–hole masses. This results in a universal crossover behavior, whereby trions become less stable than biexcitons as the transverse size of the quasi-1D nanostructure increases. The method is also capable of evaluating binding energies for electron–hole complexes in quasi-2D semiconductors such as coupled quantum wells and bilayer van der Walls bound heterostructures with advanced optoelectronic properties.


2001 ◽  
Vol 15 (28n30) ◽  
pp. 3660-3663 ◽  
Author(s):  
I.-K. OH ◽  
JAI SINGH

We present a comprehensive study of the process of exciton formation due to exciton-phonon interaction. Using the exciton-phonon interaction arising from deformation potential, piezoelectric, and polar couplings, we have calculated the rate of formation of an exciton as a function of carrier densitiies, temperatures, and center-of-mass momentum ( K ‖) in quantum wells. Our results show that excitons are dominantly formed at non-zero K ‖, which agrees very well with experiments. The formation of an exciton due to emission of longitudinal optical phonon is found to be more efficient at relatively small values of K ‖, and that due to acoustic phonon emission is more efficient at relatively large K ‖ values for carrier temperature Te-h≲50 K.


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