Scanning tunnelling microscopy and atomic force microscopy of semiconducting materials

Abstract

Michael Faraday first documented semiconducting behaviour in 1833 whenhe observed that the resistance of silver sulphide decreased with temperature,contrary to the behaviour of normal conducting materials. Up untilthe middle of the twentieth century, semiconductors were used as photodetectors,thermisters and rectifiers. In 1947 the invention of the transistor byBardeen and Brattain lead to the integrated circuit and paved the way formodern electronics. The need to produce smaller and faster transistors hasdriven research into new semiconductors.This thesis will first introduce the physics of semiconductors, followed bya description of the experimental techniques employed; scanning tunnellingmicroscopy (STM) and atomic force microscopy (AFM). Chapter 3 is concernedwith explaining anomalous scanning tunnelling spectroscopy resultsobtained for Si(100) and GaAs(110). To this end, a one-dimensional planarmodel, in which surface states affect the charge distribution and tunnellingin the system is proposed. Graphene, a novel two-dimensional material,is introduced in Chapter 4. Scanning tunnelling microscopy measurementsof graphene suspended on a metal grid are presented in this chapter. Finally,Indium antimonide Schottky contacts are investigated using conductingatomic force microscopy in Chapter 5.

Date of Award	31 Dec 2012
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Bruce Hamilton (Supervisor)