Infrared Spectroscopic Measurement of Titanium Dioxide Nanoparticle Shallow Trap State Energies

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dc.contributor.authorBurrows, Steven Prestonen
dc.contributor.committeechairMorris, John R.en
dc.contributor.committeememberBrewer, Karen J.en
dc.contributor.committeememberLong, Gary L.en
dc.contributor.departmentChemistryen
dc.date.accessioned2014-03-14T20:32:09Zen
dc.date.adate2010-03-19en
dc.date.available2014-03-14T20:32:09Zen
dc.date.issued2010-02-10en
dc.date.rdate2010-03-19en
dc.date.sdate2010-02-24en
dc.description.abstractWithin the "forbidden" range of electron energies between the valence and conduction bands of titanium dioxide, crystal lattice irregularities lead to the formation of electron trapping sites. These sites are known as shallow trap states, where "shallow" refers to the close energy proximity of those features to the bottom of the semiconductor conduction band. For wide bandgap semiconductors like titanium dioxide, shallow electron traps are the principle route for thermal excitation of electrons into the conduction band. The studies described here employ a novel infrared spectroscopic approach to determine the energy of shallow electron traps in titanium dioxide nanoparticles. Mobile electrons within the conduction band of semiconductors are known to absorb infrared radiation. As those electrons absorb the infrared photons, transitions within the continuum of the conduction band produce a broad spectral signal across the entire mid-infrared range. A Mathematical expression based upon Fermi–Dirac statistics was derived to correlate the temperature of the particles to the population of charge carriers, as measured through the infrared absorbance. The primary variable of interest in the Fermi – Dirac expression is the energy difference between the shallow trap states and the conduction band. Fitting data sets consisting of titanium dioxide nanoparticle temperatures and their associated infrared spectra, over a defined frequency range, to the Fermi–Dirac expression is used to determine the shallow electron trap state energy.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-02242010-030144en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-02242010-030144/en
dc.identifier.urihttp://hdl.handle.net/10919/31342en
dc.publisherVirginia Techen
dc.relation.haspartBurrows_SP_T_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectnanoparticlesen
dc.subjectsemiconductoren
dc.subjectsurface stateen
dc.subjectshallow trap stateen
dc.subjectinfrared spectroscopyen
dc.subjectcatalysisen
dc.subjectconduction band electronsen
dc.subjecttitanium dioxideen
dc.titleInfrared Spectroscopic Measurement of Titanium Dioxide Nanoparticle Shallow Trap State Energiesen
dc.typeThesisen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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