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Type of Document	Dissertation
Author	Fon, Warren Chung Wah
Author's Email Address	fon AT caltech.edu
URN	etd-05262004-123035
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-05262004-123035
Title	Thermal properties of nano- and microstructures
Degree	PhD
Option	Condensed Matter Physics
Advisory Committee	Advisor Name Title Michael C. Cross Committee Chair Marc W. Bockrath Committee Member Michael L. Roukes Committee Member Robert Phillips Committee Member
Keywords	nanostructure phonon scattering thermal
Date of Defense	2004-05-24
Availability	unrestricted
Abstract My work is on the experimental study of thermal conduction in nano and microscale structures. The work is divided into two parts. In the first part, we measure the thermal conductance of a suspended device from 4 to 40 K. The thermal conduction of a suspended, free-standing beam is analyzed to study the effect of phonon scattering on thermal conduction. We conclude that phonon scattering is much more severe in a nanoscale beam than bulk material. In the second part of the work, we proceed to dynamic measurement to measure the heat capacity of a suspended device. From that we study the origin of heat capacity of a silicon nitride membrane. We conclude that much of the heat capacity comes from the motional tunneling states of the ions. We use the device to demonstrate an ultrasensitive calorimeter with a very high resolution of 0.5 aJ/K. We conclude the work by applying the calorimeter to study the heat capacity of a thin adsorbed film of helium gas.
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