University of Illinois Urbana-Champaign

Interface roughness mediated optical decay and carrier dynamics in type II aluminum arsenide/gallium arsenide heterostructures

Lehner, Timothy Scott

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Description

Title
Interface roughness mediated optical decay and carrier dynamics in type II aluminum arsenide/gallium arsenide heterostructures
Author(s)
Lehner, Timothy Scott
Issue Date
1994
Doctoral Committee Chair(s)
Morkoc, Hadis
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Engineering, Electronics and Electrical
  • Physics, Condensed Matter
Language
eng
Abstract
Roughness at the interface between the well and barrier materials in quantum well systems has long been known to be an important factor determining carrier mobility in short period wells. Interface roughness (IR) has also been suggested as a possible decay mechanism in type II AlAs/GaAs heterostructures. Photoluminescence (PL) has been the primary tool used to study type II AlAs/GaAs heterostructures, and can be expected to be strongly influenced by interface roughness both through the carriers' mobility and their decay mechanism. Despite this, IR as a decay mechanism has been the subject of little to no analytical study. Additionally, the available models for IR-limited mobility do not scale with the density of scattering sites and do not include the concept of roughness-bound states. Finally, the nature of the lowest energy PL feature in type II AlAs/GaAs has been in dispute for some time. We address these issues by developing analytical expressions for the IR-limited mobility and IR-mediated optical decay in type II AlAs/GaAs systems which account for the spacing of the roughness and the existence of states bound by the roughness. Furthermore, we develop a computer model which incorporates the above mentioned analytical expressions. By comparing the results of our simulation with experimental data, we show that the unique features observed in this system through PL can be accounted for by the presence of interface roughness.
Type of Resource
text
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http://hdl.handle.net/2142/19789
Copyright and License Information
Copyright 1994 Lehner, Timothy Scott

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