Safonov, I. M.

Shulika, A. V.

Sukhoivanov, I. A.

English

Электронная библиотека БГУ

APPLICABILITY OF THE PIECEWISE-LINEAR APPROXIMATION 
OF THE POTENTIAL PROFILE OF UNDOPED MQW 
HETEROSTUCTURES
I. M. Safonov1, A. V. Shulika1, I. A. Sukhoivanov1,2 
1Kharkov National University of Radio Electronics, Ukraineл
Guanajuato University, Salama^a, Mexico
The piecewise-constant approximation of the potential profile (PP) for the 
quantum-size effects investigation in MQW heterostructures under the condi­
tions of absence of the external electric field is frequently used. To take into 
account the bias piecewise-linear functions are used [1]. Other authors [2] 
persist in the non-applicability of such an approximation and propose the self- 
consistent computing of Schrodinger and Poisson's equations. At the same 
time the first group of authors as well as the second achieved results which 
are in good accordance with experimental works and not contradict present- 
day theory of the solid-state physics of MQW. However rigorous criterions of 
the applicability of the piecewise-linear approximation (PLA) PP MQW have 
not been formulated yet.
The aims of this work are the elaboration of criterions of the piecewise- 
linear PP applicability and detection of conditions which lead to the necessity 
of the self-consistent computation. For that the comparing of self-consistent 
results and PLA results was realized.
The 6 QW structure have been chosen for the investigation [3] within which 
the varying of the QW layers' composition and thickness were carried out and 
the influence of the optical confinement layers was considered. The computa­
tions were realized in the effective mass approximation, on the assumption of 
the abruptly thin heteroboundary region and the absence of the internal QW 
layers' deformations. The bias was missing.
In the frame of the work it was shown that the main factor which limits the 
PLA usage is the big thickness of both the separate layers and the structure as 
a whole. At a big layers' thickness the PLA usage gives the wrong representa­
tion of the wave function shape and the state spectrum. At a sizeable structure 
thickness the usage of the PLA also gives the wrong information about the 
QW arrangement that leads to incorrect results concerning the QW interac­
tion. These mistakes especially appear for the case of equal QWs.
1. Anemogiannis E., Glytsis E.N., Gaylord T. K. // IEEE J. Quantum Electron. 1997. V. 33, № 5. P. 742-752.
2. PlyavenekA. G., Lyubarskii A. V // Electron. Lett. 1997. V 33, № 5. P. 392-393.
3. Lysak V. V., Kawaguchi H., Katayama T. et al. // Meeting on Creation of Ultrahigh-Speed Optical Buffer
Memory with Shift Register: Yamagata University, Yonezawa, Japan, 2003. P. 49-52.
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Applicability of the piecewise-linear approximation of the potential profile of undoped MQW heterostructures

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Applicability of the piecewise-linear approximation of the potential profile of undoped MQW heterostructures

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