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Type of Document	Dissertation
Author	McColl, Malcolm
Author's Email Address	none@none
URN	etd-10142002-162916
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-10142002-162916
Title	Electron current through thin mica films
Degree	PhD
Option	Electrical Engineering
Advisory Committee	Advisor Name Title unknown Committee Member
Keywords	none
Date of Defense	1964-02-06
Availability	unrestricted
Abstract NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Muscovite mica, cleaving every 10[Angstroms], provides a crystalline insulator with uniformly parallel surfaces of well known separation ideally suited to the study of electron transport phenomena. Using a micro-splitting technique similar to that developed by Foote and Kazan, muscovite was cleaved in a vacuum of 10(^6) Torr and metal electrodes evaporated, aluminum on one side, gold on the other. The current through 30 and 40[Angstrom] films was measured as a function of voltage and temperature and analyzed in terms of the tunneling theory of Stratton. Using the actual image-force barrier shape, the approximately symmetrical volt-ampere data gave barrier heights of [?] = 0.95 and 0.93eV for the 40 and 30[Angstrom] films, respectively, for an effective mass ratio of m*/m =0.92. The theoretical temperature dependence was observed in the 40[Angstrom] film from room temperature down to liquid nitrogen temperature (77[degrees]K). Thicker films 50 to 10,000 [Angstroms], exhibited temperature dependent volt-ampere curves linear in log I versus [square root of]V over a factor of 10:1 in voltage and a thermal activation energy of 0.55eV, lower than [t]he barrier height above possibly because of injection into polaron states. Preliminary photoelectric response data yielded [?] = 0.8eV, raising some question as to the real meaning of the [?] found from tunneling theory.
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