Degradation of field emission display phosphors

Holloway, Paul H.; Trottier, T. A.; Sebastian, J. S.; Jones, S.J.; Zhang, X.-M.; Bang, Jungsik; Abrams, Billie; Thomes, W. J.; Kim, T.-J.

doi:10.1063/1.373683

Cited by 54 publications

(39 citation statements)

References 13 publications

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“…To generate the values of t, Eqn (5) can be rearranged so that t D erf 1 2P 1 6 which returns a value of t 2 [ 4,4] for any given random number P between 0 and 1.…”

Section: Distributing Electrons Over a Surface According To A Gaussiamentioning

confidence: 99%

Monte Carlo simulation on the electron beam incident angle with spherical particles applied to the energy loss in ZnS phosphor powders

Greeff

Swart

2000

Surf. Interface Anal.

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During electron beam irradiation of ZnS phosphor powders, a non‐luminescent ZnO layer is formed on the powder due to electron‐beam‐stimulated surface reactions. As the thickness of the oxide layer increases, the energy loss in the ZnS bulk decreases with a subsequent degradation in cathodoluminescence (CL). Owing to the morphology of the phosphor powder, growth of the oxide layer leads to varying effective ZnO thicknesses. In this paper the effect of the interaction between the electron beam and the ZnO/ZnS powder particles on the energy loss in the ZnS is studied using Monte Carlo simulation techniques. In the simulation, an electron beam with a certain profile is spread according to a Gaussian distribution function over the phosphor particles. These particles consists of both flat and spherical‐shaped grains. The incident angle between the electron beam and the particle's surface is determined by using simple vector analysis. If the beam contains a sufficient number of electrons, a distribution of incident angles can be obtained. It was found that this distribution is independent upon the profile of the electron beam as long as the full width at half‐maximum (FWHM) beam diameter is larger than the size of the irradiated particles. Using these results a comparison was made between the energy loss in the ZnS particles as a function of the ZnO thickness with and without the angular distribution. A publicly available Monte Carlo code for electron trajectory simulations in solids, called CASINO, was used for this purpose. When the distribution is considered, there is a decreased energy loss in the ZnS bulk. Because the light generation during electron beam irradiation is proportional to this energy loss, the morphology of the phosphor powder also contributes to the CL degradation. Copyright © 2000 John Wiley & Sons, Ltd.

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“…To generate the values of t, Eqn (5) can be rearranged so that t D erf 1 2P 1 6 which returns a value of t 2 [ 4,4] for any given random number P between 0 and 1.…”

Section: Distributing Electrons Over a Surface According To A Gaussiamentioning

confidence: 99%

Monte Carlo simulation on the electron beam incident angle with spherical particles applied to the energy loss in ZnS phosphor powders

Greeff

Swart

2000

Surf. Interface Anal.

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“…Their data support a model called electron-stimulated surface chemical reaction (ESSCR). 4 According to this model, the reactive gas molecules adsorb onto the surface of the ZnS. The molecules are dissociated by the electron beam from molecular species to form reactive atomic species, which results in the formation of a ZnO surface layer and volatile SO 2 , 5 with the consequent loss of cathodoluminescence (CL) intensity.…”

Section: Introductionmentioning

confidence: 99%

Degradation of ZnS FED phosphors

Swart

Hillie

2000

Surf. Interface Anal.

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The degradation of cathodoluminescent brightness under prolonged electron beam excitation of phosphors has been identified as one of the outstanding critical issues for the flat-panel field emission industries. The ZnS : Cu,Al,Au phosphor powders have been subjected to electron beam bombardment of 2 keV with different electron beam current densities (2.5-88 mA cm −2 ) at an oxygen pressure of 1 × 10 −6 Torr. Auger electron spectroscopy (AES) and cathodoluminescence, both excited by the same electron beam, were used to monitor changes in surface composition and luminous efficiency during electron bombardment. Degradation was manifested by a non-luminescent ZnO layer that formed on the surface of the phosphor according to electronstimulated surface chemical reaction (ESSCR). Lower current densities lead to a higher surface reaction rate, due to a lower local temperature beneath the beam, which resulted in more severe cathodoluminescence degradation. A lower temperature beneath the electron beam may lead to an increase in the surface reaction rate due to the longer time spent by the adsorbed molecules on the surface, with a direct increase in the ESSCR probability.

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“…It was demonstrated that when these phosphors were irradiated with the beam of electrons for a long period of time they lose their CL intensity and this occured simultaneously with desorption of oxygen (O) from the phosphor surfaces. In the process, an oxygen deficient non-luminescent layer was formed on the surface whose formation could be explained by an electron stimulated surface chemical reaction (ESSCR) model proposed by Holloway and co-workers (Holloway et al, 1996(Holloway et al, , 2000. The desorption of atomic species was explained by Knotek-Fiebelman electron stimulated desorption (ESD) proposed by Knotek and Feibelman (Knotek and Feibelman, 1978).…”

Section: Introductionmentioning

confidence: 99%

“…In this case, a non-luminescent oxide layer, which is known to reduce the CL intensity of the CRT/FED phosphors, may form on the surface. For examples, it was demonstrated that when zinc sulfide (ZnS) based phosphors were exposed to a prolonged irradiation by energetic beam of electrons, the ZnS host dissociated into reactive ionic Zn 2+ and S 2-species, which in turn combined with ambient vacuum gases such as O 2 and H 2 O to form non-luminescent ZnO or ZnSO 4 layers or H 2 S gas (Swart el al., 1998;Itoh et al, 1989) as explained by the ESSCR model (Holloway et al, 1996(Holloway et al, , 2000. In the case of oxide based systems, the electron beam induced dissociation of atomic species is followed by desorption of oxygen from the surface.…”

Section: Cathodoluminescence Intensity Degradationmentioning

confidence: 99%