Abstract
In this contribution we are mainly interested in the electronic states of semiconductors quantum wells and superlattices. Such structures are simply viewed as a sequence of different semiconductor layers grown sucessively along a well defined crystalline growth direction. The carriers’ motion along this growth direction of the heterostructure (hereafter called the z direction) is then strongly modified by the presence of the various thin (≈100Å) layers, whereas the translation symmetry (at the level of the bulk unitary cells) remains for the in-plane (x,y) directions. Single quantum wells present states which are localized in space around the well region for the z motion. Double quantum wells (DQW) consist of two well layers separated by a finite barrier layer. The localized states of the isolated quantum wells interact through the barrier region (tunnel interaction) to form the DQW eigenstates. The resulting new states are delocalized over the DQW region. For example, two identical wells (same thickness and material composition) give rise to symmetrical and antisymmetrical z-dependent DQW wavefunctions (with respect to the center of the central barrier). For wells of different thicknesses (asymmetrical DQW) the tunnel coupling is less efficient and each resulting DQW state presents a preferential localization around one of the two wells, reminiscent of the localized states of the isolated wells. In other words, the tunnel coupling is less effective to mix states of distinct quantum wells wich are misaligned in energy. Semiconductor superlattices (SL) consist of a periodic repetition of a fundamental cell composed by a sequence of wells and barriers. The simplest one consists of a well and a barrier (with eventually different thicknesses).
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References
Bastard, G., Brum, J. A. and Ferreira, R.(1991), Electronic states in semiconductor heterostructures, Solid State Physics 44, 229
Altarelli, M., (1986), Band structure, impurities and excitons in superlattices, in: Heterojunctions and Semiconductor Superlattices, G. Allan, G. Bastard, N. Boccara, M. Lanoo and M. Voos, Eds. Springer Verlag, Berlin
Smith, D. L. and Mailhiot, C.(1990), Theory of semiconductor superlattice electronic structure, Rev. Mod. Phys. 62, 173
Sham, L. J. and Yan — Ten Lu (1989), Theory of electronic structure in superlattices, Journ. of Lumin. 44, 207
Luttinger, J. M. (1956), Quantum theory of cyclotron resonance in semiconductors: general theory, Phys. Rev. 102, 1030. See also Bir G. L. and Pikus G. E., (1974), Symmetry and Strain Induced Effects in Semiconductors, Wiley, New York
Böhm, D. (1951), Quantum theory, Prentice-Hall, Englewood Cliffs, N.J.
Wannier, G. H. (1962), Elements of Solid State Theory, Cambridge U. P., Cambridge, England (1959) see also Dynamics of band electrons in electric and magnetic fields, Rev. Mod. Phys. 34, 645
Nenciu, G. (1991), Dynamics of band electrons in electric and magnetic fields: rigorous justification of the effective Hamiltonians, Rev. Mod. Phys. 63, 91
Mendez, E. E. and Bastard, G. (1993), Wannier-Stark ladders and Bloch oscillations in superlattices, Physics Today 46, 34
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Bastard, G., Ferreira, R. (1995). Electronic States in Quantum Wells and Superlattices. In: Balkanski, M., Yanchev, I. (eds) Fabrication, Properties and Applications of Low-Dimensional Semiconductors. NATO ASI Series, vol 3. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-0089-2_7
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DOI: https://doi.org/10.1007/978-94-011-0089-2_7
Publisher Name: Springer, Dordrecht
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