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Nanometer scale connections to semiconductor surfaces

Extending electronic devices beyond the limitations of current micro-electronics manufacturing will require detailed knowledge of how to make contacts to semiconductor surfaces. In this work, we investigated several methods by which such connections to silicon surfaces could be achieved. Scanning tunneling microscopy (STM) was our main experimental tool, allowing direct imaging of the surfaces at the atomic level.

First, the growth of self-forming linear nanostructures of organic molecules on silicon surfaces offers a possibility of creating devices with hybrid organic-silicon functionality. We have studied the growth of many different molecules on a variety of hydrogen-terminated silicon surfaces: H-Si(100)-2x1, H-Si(100)-3x1, and H-Si(111)-1x1. We found molecular growth patterns affected by steric crowding, by sample doping level, or by exposure to ion-pump created radicals. We formed the first contiguous "L-shaped" molecular lines, and used an external electric field to direct molecular growth. We attempted to study a novel method for nanoscale information transfer along molecular lines based on excitation energy transfer.

The second part of the work focuses on the development and use of a new multiple-probe STM instrument. The design and the custom STM control software written for it are described. Connections to Si surfaces were achieved with a combination of lithographically defined metal contacts and STM tips. Two-dimensional surface conductivity of the Si(111)-7x7 surface was measured, and the effect of modifying the surface with organic molecules was investigated. A novel method, scanning tunneling fractional current imaging (STFCI), was developed to further study surface conductance. This method allowed us to determine, for the first time, that the resistance of steps on the Si(111)-7x7 surface is significantly higher than that of the surface alone.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/644
Date11 1900
CreatorsZikovsky, Janik
ContributorsWolkow, Robert (Physics), Hegmann, Frank (Physics), Freeman, Mark (Physics), Backhouse, Christopher (Electrical and Computer Engineering), Salmeron, Miquel (Materials Sciences)
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format13875471 bytes, application/pdf
RelationP. G. Piva, G. A. DiLabio, J. L. Pitters, J. Zikovsky, M. Rezeq, S. Dogel, W. A. Hofer, and R. A. Wolkow. Field regulation of single-molecule conductivity by a charged surface atom. Nature, 435(7042):658-661, 2005., S. A. Dogel, G. A. DiLabio, J. Zikovsky, J. L. Pitters, and R. A. Wolkow. Experimental and theoretical studies of trimethylene sulfide-derived nanostructures on p- and n-type H-silicon(100)-2 x 1. Journal of Physical Chemistry C, 111(32):11965-11969, 2007., J. Zikovsky, S. A. Dogel, M. B. Haider, G. A. DiLabio, and R. A. Wolkow. Self-directed growth of contiguous perpendicular molecular lines on H-Si(100) surfaces. Journal of Physical Chemistry A, 111(49):12257-12259, 2007., J. Zikovsky, S. A. Dogel, S. Sinha, G. A. DiLabio, and R. A. Wolkow. Scanning tunneling microscopy and computational study of the self-directed growth of 1,3-butadiene and 2,3-dimethyl-1,3-butadiene on hydrogen-terminated silicon(100)-2 x 1. Chemical Physics Letters, 458(1-3):117-121, 2008., J. Zikovsky, S. A. Dogel, A. J. Dickie, J. L. Pitters, and R. A. Wolkow. Reaction of a hydrogen-terminated Si(100) surface in UHV with ion-pump generated radicals. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 27(2):248-252, 2009.

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