The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Engineering Physics and Mathematics for public examination and debate in Auditorium F1 at Helsinki University of Technology (Espoo, Finland) on the 1st of June, 2004, at 12 o'clock noon.
Overview in PDF format (ISBN 951-22-7097-8) [2902 KB]
Dissertation is also available in print (ISBN 951-22-7096-X)
A single-electron transistor is the most sensitive charge detector known today. It is formed by a small piece of a conductor coupled to electrodes by tunnel junctions. At low frequencies, the charge sensitivity is limited by the 1/f-noise. The use of a radio-frequency modulation technique allows a wide operational bandwidth with negligible 1/f-noise contribution.
In this Thesis, a multiwalled carbon nanotube brought to contact with metal electrodes was demonstrated to work as a single-electron transistor. A scanning probe manipulation scheme was developed and it was used to fabricate the sample. The manipulation scheme was also employed to construct more complicated electronic carbon nanotube devices. It was shown that it is possible to construct a multiwalled carbon nanotube single-electron transistor having an equal to, or even higher charge sensitivity than a typical metallic device. The transmission-line parameters of the multiwalled carbon nanotube were estimated by using the environment-quantum-fluctuation theory.
The radio-frequency single-electron transistor setup was analyzed in depth and a simplified engineering formula for the charge sensitivity was derived. A radio-frequency single-electron transistor setup using a multiwalled carbon nanotube single-electron transistor was demonstrated in the built cryogenic high-frequency measurement system. A low-temperature high-electron-mobility-transistor amplifier was designed and built for the system. Measurements of the amplifier indicated a noise temperature of three Kelvins.
This thesis consists of an overview and of the following 9 publications:
Keywords: electron transport in mesoscopic systems, carbon nanotubes, high-frequency techniques, single-electron devices
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© 2004 Helsinki University of Technology