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Title: Fundamental Efficiency Limitations for Low Electron Energy Cathololuminescence

Abstract

The design of field emission displays is severely constrained by the universally poor cathodoluminescence (CL) efficiency of most phosphors at low excitation energies. As part of the effort to understand this phenomenon, the authors have measured the time decay of spectrally-resolved, pulsed CL and photoluminescence (PL) in several phosphors activated by rare earth and transition metal impurities, including Y{sub 2}O{sub 3}:Eu, Y{sub 2}SiO{sub 5}:Tb, and Zn{sub 2}SiO{sub 4}:Mn. Activator concentrations ranged from {approximately}0.25 to 10%. The CL decay curves are always non-linear on a log(CL)-linear(time) plot--i.e. they deviate from first order decay kinetics. These deviations are always more pronounced at short times and larger activator concentrations and are largest at low beam energies where the decay rates are noticeably faster. PL decay is always slower than that seen for CL, but these differences disappear after most of the excited species have decayed. They have also measured the dependence of steady state CL efficiency on beam energy. They find that larger activator concentrations accelerate the drop in CL efficiency seen at low beam energies. These effects are largest for the activators which interact more strongly with the host lattice. While activator-activator interactions are known to limit PL and CL efficiency inmore » most phosphors, the present data suggest that a more insidious version of this mechanism is partly responsible for poor CL efficiency at low beam energies. This enhanced concentration quenching is due to the interaction of nearby excited activators. These interactions can lead to non-radiative activator decay, hence lower steady state CL efficiency. Excited state clustering, which may be caused by the large energy loss rate of low energy primary electrons, appears to enhance these interactions. In support of this idea, they find that PL decays obtained at high laser pulse energies resemble the non-linear decays seen in the CL data.« less

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
761851
Report Number(s):
SAND2000-1992C
TRN: AH200035%%152
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: 20th IDRC Conference, Palm Beach, FL (US), 09/25/2000--09/30/2000; Other Information: PBD: 1 Aug 2000
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CATHODOLUMINESCENCE; PHOSPHORS; PHOTOLUMINESCENCE; YTTRIUM OXIDES; EUROPIUM; SILICON OXIDES; TERBIUM; ZINC OXIDES; MANGANESE

Citation Formats

SEAGER, CARLETON H, and TALLANT, DAVID R. Fundamental Efficiency Limitations for Low Electron Energy Cathololuminescence. United States: N. p., 2000. Web.
SEAGER, CARLETON H, & TALLANT, DAVID R. Fundamental Efficiency Limitations for Low Electron Energy Cathololuminescence. United States.
SEAGER, CARLETON H, and TALLANT, DAVID R. 2000. "Fundamental Efficiency Limitations for Low Electron Energy Cathololuminescence". United States. https://www.osti.gov/servlets/purl/761851.
@article{osti_761851,
title = {Fundamental Efficiency Limitations for Low Electron Energy Cathololuminescence},
author = {SEAGER, CARLETON H and TALLANT, DAVID R},
abstractNote = {The design of field emission displays is severely constrained by the universally poor cathodoluminescence (CL) efficiency of most phosphors at low excitation energies. As part of the effort to understand this phenomenon, the authors have measured the time decay of spectrally-resolved, pulsed CL and photoluminescence (PL) in several phosphors activated by rare earth and transition metal impurities, including Y{sub 2}O{sub 3}:Eu, Y{sub 2}SiO{sub 5}:Tb, and Zn{sub 2}SiO{sub 4}:Mn. Activator concentrations ranged from {approximately}0.25 to 10%. The CL decay curves are always non-linear on a log(CL)-linear(time) plot--i.e. they deviate from first order decay kinetics. These deviations are always more pronounced at short times and larger activator concentrations and are largest at low beam energies where the decay rates are noticeably faster. PL decay is always slower than that seen for CL, but these differences disappear after most of the excited species have decayed. They have also measured the dependence of steady state CL efficiency on beam energy. They find that larger activator concentrations accelerate the drop in CL efficiency seen at low beam energies. These effects are largest for the activators which interact more strongly with the host lattice. While activator-activator interactions are known to limit PL and CL efficiency in most phosphors, the present data suggest that a more insidious version of this mechanism is partly responsible for poor CL efficiency at low beam energies. This enhanced concentration quenching is due to the interaction of nearby excited activators. These interactions can lead to non-radiative activator decay, hence lower steady state CL efficiency. Excited state clustering, which may be caused by the large energy loss rate of low energy primary electrons, appears to enhance these interactions. In support of this idea, they find that PL decays obtained at high laser pulse energies resemble the non-linear decays seen in the CL data.},
doi = {},
url = {https://www.osti.gov/biblio/761851}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 01 00:00:00 EDT 2000},
month = {Tue Aug 01 00:00:00 EDT 2000}
}

Conference:
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