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Electron Mobility in One (Two)‐Side Modulation‐Doped GaAs/Al x Ga 1—x As Asymmetric Quantum Wells
Author(s) -
Lima F.M.S.,
Fanyao Qu,
Nunes O.A.C.,
Fonseca A.L.A.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(200105)225:1<43::aid-pssb43>3.0.co;2-d
Subject(s) - condensed matter physics , scattering , ionized impurity scattering , quantum well , electron , electron mobility , effective mass (spring–mass system) , phonon scattering , fermi gas , doping , impurity , ionization , phonon , chemistry , physics , atomic physics , quantum mechanics , ion , laser
We have calculated the electron mobility in one (two)‐side modulation‐doped GaAs/Al x Ga 1— x As asymmetric quantum wells. Coupled Schrödinger and Poisson equations were solved through the extended Fang‐Howard variational method by considering the effective mass approximation, finite well barriers, the exchange‐correlation correction to the effective potential and electrons in the quantum limit. The results were used to determine the electron mobility where only the relevant scattering processes, namely acoustic‐phonon, ionized impurity, alloy disorder and interface roughness were considered. The partials and total mobility dependences on temperature were found and from the acoustic‐phonon scattering contribution we have determined the temperature coefficient α . It is shown that the ionized impurity scattering is the dominant mechanism and that alloy disorder scattering overcomes acoustic‐phonon scattering at very low temperatures. The ionized impurity and total mobilities were also related to the spacer width and the two‐dimensional electron gas density. We have also considered the inclusion of a second modulation‐doping spike on the reverse side of the quantum well and its effect on mobility has been discussed.