Photoluminescence studies of carrier dynamics in (indium(x),aluminum(x)) gallium(1-x) arsenic/gallium arsenide quantum well structures
Griffiths, Christopher Owen John
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https://hdl.handle.net/2142/23283
Description
Title
Photoluminescence studies of carrier dynamics in (indium(x),aluminum(x)) gallium(1-x) arsenic/gallium arsenide quantum well structures
Author(s)
Griffiths, Christopher Owen John
Issue Date
1994
Doctoral Committee Chair(s)
Klein, Miles V.
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Physics, Condensed Matter
Language
eng
Abstract
This thesis discusses carrier dynamics of III-V semiconductor quantum well structures probed by photoluminescence techniques in In$\sb{\rm x}$Ga$\sb{\rm 1-x}$As/GaAs and Al$\sb{\rm x}$Ga$\sb{\rm 1-x}$As/GaAs quantum well systems. Photoluminescence is a useful nondestructive probe of direct-gap quantum structures because the exciton population responsible for the measured luminescence is sensitive to well width, alloy composition, strain (in lattice-mismatched structures), and interface roughness. Continuous wave (cw) and time-resolved photoluminescence, and photoluminescence excitation (PLE) measurements were used to gain insight into the physics of GaAs alloy quantum structures.
The strain study in Chapter 4 measured the strain in individual quantum wells (within In$\sb{\rm x}$Ga$\sb{\rm 1-x}$As/GaAs multiquantum well samples) by analyzing excitonic luminescence as a function of incident laser energy. These results led to the equilibrium strain model which describes strain due to lattice-mismatch being shared between well and barrier layers in strain-relaxed multiquantum well structures. The small feature study of Chapter 5 investigates the presence of an absorption dip in the photoluminescence spectra of an In$\sb{0.10}$Ga$\sb{0.90}$As single quantum well and five quantum well sample. The dip is explained by fast relaxation of mobile excitons from the barrier material into the quantum well layer. Chapter 6 investigates the effect of interface roughness on tunneling times between narrow well and wide well in Al$\sb{\rm x}$Ga$\sb{\rm 1-x}$As/GaAs asymmetric coupled quantum well structures.
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