Electron Current Through Thin Mica Films

Citation

McColl, Malcolm (1964) Electron Current Through Thin Mica Films. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/7ENX-8503. https://resolver.caltech.edu/CaltechETD:etd-10142002-162916

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.

Thesis Files