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|Title:||Phonon and Alloy-Clustering Effects in Aluminum Gallium Arsenide-Gallium Arsenide Quantum-Well Heterostructures|
|Author(s):||Vojak, Bruce Arthur|
|Department / Program:||Electrical Engineering|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Engineering, Electronics and Electrical|
|Abstract:||Phonon and alloy-clustering effects in the luminescence characteristics of Al(,x)Ga(,1-x)As-GaAs quantum-well heterostructures (QWH) are studied. In the form of a QWH, GaAs is shown to lase over a (TURN)0.5 eV energy range between (TURN)E(,g) (GaAs)-36 meV and (TURN)E(,g)(GaAs)+445 meV.
Phonon-sideband laser operation at energies below E(,g)(GaAs) is induced in undoped GaAs layers (L(,z) (TURN)200-500 (ANGSTROM)) that, on their own, do not lase at 77 K at E < E(,g)(GaAs). Induced phonon-sideband laser operation is used to obtain a measurement of the LO-phonon energy in GaAs of (H/2PI)(omega)(,LO)(DBLTURN)36.1 meV. The contribution of LO phonons, emitted during the process of carrier thermalization from the wide-gap Al(,x)Ga(,1-x)As confining layers to the narrow-gap active region, to QWH and double heterostructure laser operation is confirmed.
Alloy clustering in thin Al(,x)Ga(,1-x)As (x < 1) barrier layers is observed to contribute to spontaneous and stimulated emission in the energy range between E(,g)(GaAs) and the lowest energy confined-carrier transition of an ideal QWH. For Al(,x)Ga(,1-x)As layers grown by the metalorganic-chemical vapor deposition process, and Al-Ga cluster size of (TURN)40 (ANGSTROM) is estimated. The substitution of cluster-free, binary AlAs layers for the Al(,x)Ga(,1-x)As barriers eliminates alloy clustering and results in high-energy, narrow-linewidth spontaneous and stimulated emission from a QWH. Visible-red laser operation as high as 445 meV (77 K) and 400 meV (300 K) above E(,g)(GaAs) is observed from a QWH with an AlAs-GaAs cluster-free active region.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
|Date Available in IDEALS:||2014-12-12|
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Dissertations and Theses - Electrical and Computer Engineering
Dissertations and Theses in Electrical and Computer Engineering
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois