Abstract
In this thesis, electron transport in quantum and ballistic devices was studied. The devices studied here were quantum wires, planar quantum dots, ballistic rectifiers, artificial functional materials, and three-terminal ballistic junctions. The possible application of such devices in the future nanoelectronics was also investigated.
In an electron waveguide, with an abrupt change in the geometry at the entrance and the exit, conductance oscillations, superimposed on conventional conductance plateaus, were observed. These oscillations were attributed to formation of longitudinal, resonant electron states in the waveguide, in analogy with optical Fabry-Perot effects.
The Coulomb charging effects and the resonant tunneling through the lowest quantized energy level of the heterostructurally defined, planar quantum dots were studied.
The ballistic rectifiers were fabricated to be small enough to show ballistic effects even at room temperature. In analogy to the ballistic rectifiers, the artificial functional nanomaterial was proposed and fabricated. The ballistic rectifiers as well as the artificial nanomaterials showed functionality at room temperature and at frequencies up to at least 50 GHz. Quantum effects in the transport behavior of the nano-scale ballistic rectifiers and the artificial materials were found to be dominant at low temperatures.
Nonlinear electrical properties of three-terminal ballistic junctions were investigated. Three-terminal ballistic junctions were found to show nonlinear current-voltage, and voltage-voltage characteristics tunable by voltages applied either to one of the branches of the junction or to an external capacitively-coupled gate. These nonlinear electrical properties are observable even at room temperature and are therefore interesting from an application point of view. Integrated devices, such as the frequency multipliers based on a three-terminal ballistic junction were proposed and demonstrated. The fabricated frequency multipliers showed frequency doubling and gain at room temperature.
In an electron waveguide, with an abrupt change in the geometry at the entrance and the exit, conductance oscillations, superimposed on conventional conductance plateaus, were observed. These oscillations were attributed to formation of longitudinal, resonant electron states in the waveguide, in analogy with optical Fabry-Perot effects.
The Coulomb charging effects and the resonant tunneling through the lowest quantized energy level of the heterostructurally defined, planar quantum dots were studied.
The ballistic rectifiers were fabricated to be small enough to show ballistic effects even at room temperature. In analogy to the ballistic rectifiers, the artificial functional nanomaterial was proposed and fabricated. The ballistic rectifiers as well as the artificial nanomaterials showed functionality at room temperature and at frequencies up to at least 50 GHz. Quantum effects in the transport behavior of the nano-scale ballistic rectifiers and the artificial materials were found to be dominant at low temperatures.
Nonlinear electrical properties of three-terminal ballistic junctions were investigated. Three-terminal ballistic junctions were found to show nonlinear current-voltage, and voltage-voltage characteristics tunable by voltages applied either to one of the branches of the junction or to an external capacitively-coupled gate. These nonlinear electrical properties are observable even at room temperature and are therefore interesting from an application point of view. Integrated devices, such as the frequency multipliers based on a three-terminal ballistic junction were proposed and demonstrated. The fabricated frequency multipliers showed frequency doubling and gain at room temperature.
Original language | English |
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Qualification | Doctor |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 2003 Jun 6 |
Publisher | |
ISBN (Print) | 91-628-5707-X |
Publication status | Published - 2003 |
Bibliographical note
Defence detailsDate: 2003-06-06
Time: 13:15
Place: Dept of Physics, room B, Lund Institute of Technology
External reviewer(s)
Name: Aoyagi, Yoshinobu
Title: Professor
Affiliation: Japan
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1.Conductance oscillations induced by longitudinal resonant states in heteroepitaxially defined GaInAs/InP elecron waveguides Qin Wang, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert, Weidong Sheng, I. Shorubalko, and H. Q. Xu Appl. Phys. Lett 76, 2274 (2000)
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2.Coulomb blockade and resonant tunneling in etched and regrown GaInAs/InP quantum dots I. Shorubalko, P. Ramvall, H. Q. Xu, I. Maximov, W. Seifert, P. Omlong and L. Samuelson Semicond. Sci. Technol. 16, 741-744 (2001)
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3.Room-temperature and 50 GHz operation of a functional nanomaterial A. M. Song, P. Omling, L. Samuelson, W. Seifert, I. Shorubalko, and H. Zirath Appl. Phys. Lett 79, 1357 (2001)
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4.Operation of InGaAs/InP-based ballistic rectifiers at room-temperature and frequencies up to 50 GHz A. M. Song, P. Omling, L. Samuelson, W. Seifert, I. Shorubalko, and H. Zirath Jpn. J. Appl. Phys. 40, L909 (2001)
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5.Quantum behaviour in nanoscale ballistic rectifiers and artificial materials A. Löfgren, I. Shorubalko, P. Omling, and A. M. Song Phys. Rev. B 67, 195309 (2003)
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6.Nonlinear operation of GaInAs/InP-based three-terminal ballistic junctions I. Shorubalko, H. Q. Xu, I. Maximov, P. Omling, L. Samuelson, and W. Seifert Appl. Phys. Lett 79, 1357 (2001)
Article: 7.Tuneable nonlinear current-voltage characteristics of three terminal ballistic junctionsI. Shorubalko, H. Q. Xu, P. Omling, L. Samuelsonmanuscript (2003)
Article: 8.A novel Frequency-Multiplication device based on three-Terminal ballistic junctionI. Shorubalko, H. Q. Xu, I. Maximov, D. Nilsson, P. Omling, L. Samuelson, and W. SeifertIEEE Electron Device Lett., vol. 23, pp. 377-379 (2002)
Subject classification (UKÄ)
- Condensed Matter Physics
Free keywords
- III-V semiconductors
- low-dimensional structures
- nanostructures
- ballistic rectifiers
- three-terminal ballistic junctions
- quantum wires
- planar quantum dots
- logic gates
- harmonic generation
- InP
- GaInAs
- nanoelectronics
- Fysik
- Physics
- nonlinear transport
- electron transport
- quantum nanodevices
- ballistic nanodevices
- Fysicumarkivet A:2003:Shorubalko