Resonant Tunneling in Laterally Confined Quantum Structures
(2001)- Abstract
- In the thesis, three-dimensionally confined resonant tunneling structures were studied experimentally. Two approaches were used for obtaining quantum confinement: gate-defined lateral constriction of double barrier structures, and epitaxial growth of self-assembled quantum dots. In addition, the thesis deals with the basic development of large-area double barrier resonant tunneling diodes, as a starting point for more advanced quantum dot structures.
Large area double barrier resonant tunneling diodes in several material systems were investigated: GaAs/Ga0.5In0.5P, GaAs/GaAs0.2P0.8, GaAs/GaP, and Ga0.5In0.5As/InP. Emphasis was placed on GaInP/GaAs structures, which were optimized in terms of well width and of doping... (More) - In the thesis, three-dimensionally confined resonant tunneling structures were studied experimentally. Two approaches were used for obtaining quantum confinement: gate-defined lateral constriction of double barrier structures, and epitaxial growth of self-assembled quantum dots. In addition, the thesis deals with the basic development of large-area double barrier resonant tunneling diodes, as a starting point for more advanced quantum dot structures.
Large area double barrier resonant tunneling diodes in several material systems were investigated: GaAs/Ga0.5In0.5P, GaAs/GaAs0.2P0.8, GaAs/GaP, and Ga0.5In0.5As/InP. Emphasis was placed on GaInP/GaAs structures, which were optimized in terms of well width and of doping concentration.
Gate-defined lateral confinement was achieved by a buried metal gate positioned 30 nm above a GaInP/GaAs double barrier. The Schottky depletion from the metal directs the current to a designed opening in the gate. The opening constitutes a conducting channel through the depleted semiconductor, where an applied gate voltage alters the effective width of the channel. Room-temperature transistor action was measured in structures with large opening area, and multiple current peaks in the low-temperature current-voltage characteristics of small-area devices indicate that lateral quantum confinement was achieved. The gate and magnetic-field dependence of the features obtained showed qualitative agreement with calculations performed on a coupled 1D-0D-1D quantum system.
Low-temperature electron transport through self-assembled InAs dots in InP barriers showed several distinct current peaks. Utilizing As/P exchange reactions on the InP surface, extremely low dot densities (N=4e6 cm-2) was achieved, corresponding to approximately 150 quantum dots in a macroscopic mesa structure. Transport through single- and double-dot layers have been investigated. In the stacked samples, a peak-to-valley ratio of 85 was obtained. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/41579
- author
- Gustafson, Boel LU
- supervisor
- opponent
-
- Dr Seabaugh, Alan, University of Notre Dame
- organization
- publishing date
- 2001
- type
- Thesis
- publication status
- published
- subject
- keywords
- gravitation, relativity, quantum mechanics, classical mechanics, Mathematical and general theoretical physics, Fysik, Physics, High peak-to-valley ratio, Lateral confinement, Quantum dots, Resonant tunneling, Self-assembled quantum dots, Schottky depletion, Buried metal gate, Electron transport, Magnetic-field dependence, Energy level width, Tunneling transistors, Mode coupling, statistical physics, thermodynamics, Matematisk och allmän teoretisk fysik, klassisk mekanik, kvantmekanik, relativitet, statistisk fysik, termodynamik, Technological sciences, Teknik, Fysicumarkivet A:2001:Gustafson
- pages
- 106 pages
- publisher
- Division of Solid State Physics, Department of Physics, Lund University,Box 118, SE-221 00 Lund, Sweden,
- defense location
- Sal B Department of Physics
- defense date
- 2001-05-04 10:15:00
- external identifiers
-
- other:ISRN: LUFTD2/TFFF--01/0059--SE
- ISBN
- 91-7874-123-8
- language
- English
- LU publication?
- yes
- id
- 43402fe6-e9c9-4d9d-9e99-dcd2954e3610 (old id 41579)
- date added to LUP
- 2016-04-04 10:47:44
- date last changed
- 2018-11-21 21:00:48
@phdthesis{43402fe6-e9c9-4d9d-9e99-dcd2954e3610,
abstract = {{In the thesis, three-dimensionally confined resonant tunneling structures were studied experimentally. Two approaches were used for obtaining quantum confinement: gate-defined lateral constriction of double barrier structures, and epitaxial growth of self-assembled quantum dots. In addition, the thesis deals with the basic development of large-area double barrier resonant tunneling diodes, as a starting point for more advanced quantum dot structures.<br/><br>
<br/><br>
Large area double barrier resonant tunneling diodes in several material systems were investigated: GaAs/Ga0.5In0.5P, GaAs/GaAs0.2P0.8, GaAs/GaP, and Ga0.5In0.5As/InP. Emphasis was placed on GaInP/GaAs structures, which were optimized in terms of well width and of doping concentration.<br/><br>
<br/><br>
Gate-defined lateral confinement was achieved by a buried metal gate positioned 30 nm above a GaInP/GaAs double barrier. The Schottky depletion from the metal directs the current to a designed opening in the gate. The opening constitutes a conducting channel through the depleted semiconductor, where an applied gate voltage alters the effective width of the channel. Room-temperature transistor action was measured in structures with large opening area, and multiple current peaks in the low-temperature current-voltage characteristics of small-area devices indicate that lateral quantum confinement was achieved. The gate and magnetic-field dependence of the features obtained showed qualitative agreement with calculations performed on a coupled 1D-0D-1D quantum system.<br/><br>
<br/><br>
Low-temperature electron transport through self-assembled InAs dots in InP barriers showed several distinct current peaks. Utilizing As/P exchange reactions on the InP surface, extremely low dot densities (N=4e6 cm-2) was achieved, corresponding to approximately 150 quantum dots in a macroscopic mesa structure. Transport through single- and double-dot layers have been investigated. In the stacked samples, a peak-to-valley ratio of 85 was obtained.}},
author = {{Gustafson, Boel}},
isbn = {{91-7874-123-8}},
keywords = {{gravitation; relativity; quantum mechanics; classical mechanics; Mathematical and general theoretical physics; Fysik; Physics; High peak-to-valley ratio; Lateral confinement; Quantum dots; Resonant tunneling; Self-assembled quantum dots; Schottky depletion; Buried metal gate; Electron transport; Magnetic-field dependence; Energy level width; Tunneling transistors; Mode coupling; statistical physics; thermodynamics; Matematisk och allmän teoretisk fysik; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Technological sciences; Teknik; Fysicumarkivet A:2001:Gustafson}},
language = {{eng}},
publisher = {{Division of Solid State Physics, Department of Physics, Lund University,Box 118, SE-221 00 Lund, Sweden,}},
school = {{Lund University}},
title = {{Resonant Tunneling in Laterally Confined Quantum Structures}},
year = {{2001}},
}