All Physics Faculty Presentations

Document Type

Poster

Journal/Book Title/Conference

Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) 2012 Annual Report

Publication Date

10-14-2012

Abstract

Optical coatings of disordered thin film SiO2/SiOx dielectric samples on reflective metal substrates exhibited cathodoluminescence under electron beam irradiation. Measurements of the absolute radiance and emission spectra as functions of incident electron energy, flux and power over a range of sample temperatures are reported. Radiance reached a saturation plateau at high incident electron power. Well below saturation radiance scaled with deposited power, that is linearly with incident power for lower-energy non-penetrating electrons and decreasing with increasing energy for penetrating radiation. Four bands were observed in spectral measurements from 300 nm to 1000 nm. Changes in peak intensity and shifts in peak energies as functions of temperature are described. The observations are explained in terms of a simple disordered band theory model and the transitions that take place between electrons in extended conduction states and localized trapped states associated with structural or compositional defects in the highly disordered insulating materials; this provides a fundamental basis for understanding the dependence of cathodoluminescence on irradiation time, incident flux and energy, and sample thickness and temperature.

Comments

Poster presented at the 2012 IEEE Conference on Electrical Insulation and Dielectric Phenomena;Montréal, Québec, CANADA October 14 – 17, 2012

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