Effect of Residual Stress on the Luminescence Lifetime of R‐Line Emission from Polycrystalline Alumina Formed by Oxidation

Abstract

In contrast to the simple exponential decay of the luminescence lifetime of the R lines observed from stressed and unstressed single crystals, the luminescence decay from polycrystalline alumina, formed by the oxidation of a ferritic FeCrAlY alloy, is found to fit a stretched exponential. A stretch exponential is found to fit all the luminescence decays in the polycrystalline alumina and the dependence of the stretch parameters under biaxial residual stress and under uniaxial stress is reported. The mean lifetime varies linearly with the residual stress, as monitored by the R2-line shift. Using established piezospectroscopic relations, the stress dependence of the lifetime is found to be onethird of the hydrostatic pressure under uniaxial stress and two thirds under biaxial stresses. In contrast, the stretch exponent doesnt vary with stress.

Recombination dynamics of deep defect states in zinc oxide nanowires

“…One of the main difficulties in the investigation of timeresolved photoluminescence phenomena often lies in the interpretation of the results. As a matter of fact, when the decay of the PL signal does not follow the simple single exponential behaviour, several choices for a reasonable decay function (such as double exponential [16] or Kohlraush stretched exponential function [17,18]) can usually provide a satisfactory phenomenological description of the results. In cases in which a simple qualitative discussion is required, a 'good' fitting function can be used as a phenomenological tool without attempting to relate the fitting parameters to physical quantities.…”

Review: Coefficients for Stress, Temperature, and Composition Effects in Fluorescence Measurements of Alumina

“…At least part of the motivation for the polycrystalline research was to investigate the stress fields arising in polycrystalline alumina responsible for microcracking-the spontaneous localized cracking that occurs in polycrystalline alumina on cooling as a consequence of the anisotropic structure and thermal expansion of corundum [39][40][41]. From the 1990s onward, although there were many notable fundamental studies of the phenomenon [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], the shift in energy of R lines with stress was largely confined to the applied domain, detailed in numerous works, such as: measurement of stress in bulk Al2O3 polycrystals [42,[58][59][60][61][62][63][64][65][66][67]; in bulk Al2O3-ZrO2 composites [68][69][70][71][72][73][74][75][76][77][78]; in sapphire or composite fibers, free or in matrices [79][80]…”

Partículas micro e submicrométricas luminescentes de alumina dopadas com íons cromo: síntese por pirólise de aerossol, estudo estrutural e espectroscópico para aplicação em fotônica

“…O coríndon é muito utilizado como abrasivo, produto comercial obtido em fornos elétricos a partir da bauxita, e também, gemas na fabricação de joias preciosas e ornamentos, devido à sua elevada dureza e exuberante beleza. Por outro lado, avaliando suas propriedades espectroscópicas, cristais de rubi também podem ser utilizados na aferição de temperatura [39],…”