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Nanofabrication and Characterization for Applications in Biochemistry and Molecular Electronics

Tegenfeldt, Jonas LU (1997)
Abstract
As man-made structures are made increasingly smaller it becomes possible to conduct measurements on single cells, molecules and eventually atoms. In this thesis prerequisites for making this possible are discussed. The underlying thought is that the structures should be used in biological and organic based applications. The discussion is kept in three domains: fabrication, characterization and applications. Fabrication of small structures is mainly accomplished using standard techniques from the semiconductor industry such as UV-lithography or electron beam lithography. For biological and sensor applications the size is important, not the level of complexity. Therefore, a wider range of fabrication methods is available than for... (More)
As man-made structures are made increasingly smaller it becomes possible to conduct measurements on single cells, molecules and eventually atoms. In this thesis prerequisites for making this possible are discussed. The underlying thought is that the structures should be used in biological and organic based applications. The discussion is kept in three domains: fabrication, characterization and applications. Fabrication of small structures is mainly accomplished using standard techniques from the semiconductor industry such as UV-lithography or electron beam lithography. For biological and sensor applications the size is important, not the level of complexity. Therefore, a wider range of fabrication methods is available than for manufacturing integrated circuits. Chemical treatment of surfaces, alternative material systems and small scale metallic etching is presented here. The discussion on characterization is focused on scanning probe microscopy and in particular on scanning force microscopy (SFM). SFM allows atomic or nearly atomic resolution on non-conducting samples. In addition it gives a material dependent contrast. This has had a large impact in the bioscience field. The resulting images are deceptively convincing and show in great detail the sample surface as well as mappings of specific force interactions. On the other hand the critical evaluation of images has not had as large a development as the acquiring of images themselves. Artifacts arise due to the finite size of the tip and the rotation of the tip during acquisition. In the thesis examples of artifacts are presented and the effects of the tip and the cantilever on the geometry will be discussed. It is found that for patches which present higher friction, the twisting of the cantilever will contribute to a larger apparent width in the image. By miniaturizing electrode structures, quantitative improvements on sensor structures is the result as well as qualitatively new phenomena. Many of the effects relevant to sensor technology is discussed in the thesis. The standard techniques from the semiconductor industry cannot be directly transferred to biochemical applications or molecular electronics. The material selection is very important. Here some examples of the use of silicon electrodes as well as nanostructured surfaces will be presented. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Göpel, Wolfgang, Tübingen University
organization
publishing date
type
Thesis
publication status
published
subject
keywords
nanofabrication, chemical functionalization, silanization, scanning force microscopy, AFM, lateral forces, image processing, admittance spectroscopy, Physics, biosensors, Biokemi, Fysicumarkivet A:1997:Tegenfeldt, Metabolism, Fysik, Biochemistry, localized etching
pages
210 pages
publisher
Division of Solid State Physics, Lund University, P.O. Box 118, S-221 00 Lund, Sweden,
defense location
Hörsalen, Kårhuset
defense date
1997-05-23 10:15
external identifiers
  • Other:ISRN: LUFTD2/(TFFF-0045)1-210
ISBN
91-628-2575-5
language
English
LU publication?
yes
id
f8db534f-8f27-4eef-b825-23a8809e5de4 (old id 29262)
date added to LUP
2007-06-15 08:36:00
date last changed
2016-09-19 08:45:05
@phdthesis{f8db534f-8f27-4eef-b825-23a8809e5de4,
  abstract     = {As man-made structures are made increasingly smaller it becomes possible to conduct measurements on single cells, molecules and eventually atoms. In this thesis prerequisites for making this possible are discussed. The underlying thought is that the structures should be used in biological and organic based applications. The discussion is kept in three domains: fabrication, characterization and applications. Fabrication of small structures is mainly accomplished using standard techniques from the semiconductor industry such as UV-lithography or electron beam lithography. For biological and sensor applications the size is important, not the level of complexity. Therefore, a wider range of fabrication methods is available than for manufacturing integrated circuits. Chemical treatment of surfaces, alternative material systems and small scale metallic etching is presented here. The discussion on characterization is focused on scanning probe microscopy and in particular on scanning force microscopy (SFM). SFM allows atomic or nearly atomic resolution on non-conducting samples. In addition it gives a material dependent contrast. This has had a large impact in the bioscience field. The resulting images are deceptively convincing and show in great detail the sample surface as well as mappings of specific force interactions. On the other hand the critical evaluation of images has not had as large a development as the acquiring of images themselves. Artifacts arise due to the finite size of the tip and the rotation of the tip during acquisition. In the thesis examples of artifacts are presented and the effects of the tip and the cantilever on the geometry will be discussed. It is found that for patches which present higher friction, the twisting of the cantilever will contribute to a larger apparent width in the image. By miniaturizing electrode structures, quantitative improvements on sensor structures is the result as well as qualitatively new phenomena. Many of the effects relevant to sensor technology is discussed in the thesis. The standard techniques from the semiconductor industry cannot be directly transferred to biochemical applications or molecular electronics. The material selection is very important. Here some examples of the use of silicon electrodes as well as nanostructured surfaces will be presented.},
  author       = {Tegenfeldt, Jonas},
  isbn         = {91-628-2575-5},
  keyword      = {nanofabrication,chemical functionalization,silanization,scanning force microscopy,AFM,lateral forces,image processing,admittance spectroscopy,Physics,biosensors,Biokemi,Fysicumarkivet A:1997:Tegenfeldt,Metabolism,Fysik,Biochemistry,localized etching},
  language     = {eng},
  pages        = {210},
  publisher    = {Division of Solid State Physics, Lund University, P.O. Box 118, S-221 00 Lund, Sweden,},
  school       = {Lund University},
  title        = {Nanofabrication and Characterization for Applications in Biochemistry and Molecular Electronics},
  year         = {1997},
}