Graduation Semester and Year

2008

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Materials Science and Engineering

Department

Materials Science and Engineering

First Advisor

Jin Seong Koh

Abstract

Single-electron devices, in which the transport and storage of individual electrons is precisely controlled, have many potential benefits in the field of electronics, optics, and sensors. Fabrication of these devices requires the arrangement of device components (Coulomb island, source, drain, and gate electrodes) with nanometer scale precision. Although several methods have successfully demonstrated single-electron behavior, large-scale fabrication of single-electron devices has not been possible.This research aims to - * Come up with a method which would allow the fabrication of single-electron devices on a large scale,* Make the fabrication method compatible with current CMOS technology, and,* Enable room-temperature operation of the single-electron devices.A major achievement of this research has been the creation of a new single-electron device structure within the framework of current CMOS technology which has allowed for the fabrication of single-electron devices on a large scale and in parallel process. This was made possible by employing a vertical electrode configuration where the source and the drain electrodes were separated by a thin layer of dielectric medium (~10 nm). Next, Coulomb islands were attached to the exposed sidewalls of the dielectric film using a combination of colloidal and surface chemistry. Individually addressable gate electrodes were then incorporated in devices, also in complete parallel processing.Subsequent I-V measurements of these devices have yielded Coulomb blockade, Coulomb staircase, and Coulomb oscillations at room temperature and at low temperature. A systematic study of the single-electron charging/tunneling was carried out utilizing different sizes of Coulomb islands. The dependence of the nature of the Coulomb blockade and Coulomb staircase on nanoparticle size, temperature, and location of the Coulomb island were also investigated. Simulations based on the orthodox theory are in excellent agreement with the experimental results.Another challenge toward the realization of nanoscale devices is to develop a technique which enables an accurate and reliable positioning of nanostructures onto the targeted locations. Combining wet chemistry and CMOS fabrication technology, a method was developed which enables precise positioning of nanoparticles in the gap between two electrodes. Such precise positioning of nanoparticles could be utilized to improve the yield of single-electron devices.

Disciplines

Engineering | Materials Science and Engineering

Comments

Degree granted by The University of Texas at Arlington

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