Advances in field emission displays phosphors

Holloway, Paul H.; Trottier, T. A.; Abrams, Billie; Kondoleon, Caroline A.; Jones, S.J.; Sebastian, J. S.; Thomes, W. J.; Swart, H.C.

doi:10.1116/1.590634

Cited by 165 publications

(126 citation statements)

References 45 publications

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“…It has been shown that understanding the role of a surface in photo-and cathodoluminescence phenomena requires studying the nature of the surface states, local electric fields due to trapped charges and the band structure at surfaces [70][71][72]. For example, luminescence intensity in Y 2 O 3 :Eu and Y 2 SiO 5 :Tb (under low-voltage CR excitation) can to an extent be controlled by impressed external electric fields over phosphor layer [73].…”

Section: Final Research Task Reportsmentioning

confidence: 99%

Multi-Photon Phosphor Feasibility Research

Graham¹,

Chow²

2003

199

341

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Section: Final Research Task Reportsmentioning

confidence: 99%

Multi-Photon Phosphor Feasibility Research

Graham¹,

Chow²

2003

199

341

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“…Thus, the penetration depth of the primary electrons is small and the phosphors exhibit more severe surface degradation. During operation, the phosphor decomposition products generated by electron stimulated processes can poison the emitter cathodes [2]. This lowers the efficiency of the phosphor and shortens the life of the device.…”

mentioning

confidence: 99%

“…However, vacuum fluorescent displays (VFD) utilizing these mixes have a short life time compared to those using traditional high conductivity ZnO:Zn. One serious impediment which limits the use of conventional sulfide phosphors is the electron stimulated decomposition which generates harmful gases such as S, SO and SO 2 [2]. The sulfur related gases coming from the phosphor can dramatically reduce the electron emission efficiency of the cathodes and the degradation of the phosphor surface also leads to deteriorated phosphor performance.…”

mentioning

confidence: 99%

Uniform and continuous Y2O3 coating on ZnS phosphors

Park

Yasuda

Wagner

et al. 2000

Materials Science and Engineering: B

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An investigation is reported of the coating of ZnS by Y 2 O 3 using a sol -gel process. Yttrium isopropoxide was used as the precursor material and was dissolved in a toluene/isopropanol solution. The solution was refluxed at an elevated temperature before the phosphors were added. The coated phosphors were then fired in air to convert the hydroxide to oxide. Scanning electron microscopy confirmed the formation of coatings on ZnS powders. The coating morphology was strongly dependent on the sol-gel processing parameters and the range of solution concentration and pH values necessary to form continuous coatings were determined. The cathodoluminescence properties of the coated phosphors were also investigated and an improvement in phosphor maintenance was observed.

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“…Low-voltage operation can also reduce electron beam stimulated chemical reactions which have been associated with phosphor and cathode degradation in FEDs. 2 Because of the small penetration depth at low voltages, the loss processes are believed to be associated with surface recombination, and thus, the surface coating and encapsulation of phosphors is an important technique to improve low-voltage cathodoluminescence (CL) and chemical stability and to reduce outgassing. Coatings can also reduce phosphor surface degradation (such as oxidation) associated with display fabrication processes thus reducing the surface dead-layer thickness and passivating surface recombination centers.…”

mentioning

confidence: 99%

Thin SiO₂ coating on ZnS phosphors for improved low-voltage cathodoluminescence properties

et al. 2000

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A significant improvement (40-60%) was reported in the low voltage (100-1000V) cathodoluminescence efficiency of ZnS phosphors coated with SiO 2 by the sol-gel technique. The properties of the coatings were found to be critically dependent upon the precursor concentration, pH value and the temperature of the solution with optimum performance being obtained for a SiO 2 concentration of 1.0 wt%, pH values between 7-9, and a solution temperature of 83°C. The efficiency curves exhibited a characteristic voltage dependence which was analyzed by a one-dimensional numerical model. Enhanced low voltage efficiency was attributed to a reduction of surface recombination and the actual shape of the efficiency curve was determined by the interplay between the reduction of surface recombination and energy losses in the SiO 2 coating.The physical mechanism of phosphor excitation in the field emission display (FED) and conventional cathode ray tube (CRT) displays is the same. However, FEDs operate at much lower voltages, which makes it necessary to use higher current densities in order to maintain the same output luminance.1 At low acceleration voltages, the electron penetration depth is small compared to the phosphor particle size, and therefore, phosphors exhibit low efficiency due to the loss processes associated with the surface. However, there are many advantages that can be achieved by very low voltage (<500 V) operation; more simple FED structures can be utilized because the need for focusing electrodes is eliminated, arcing is reduced, and switched anode operation becomes feasible. Low-voltage operation can also reduce electron beam stimulated chemical reactions which have been associated with phosphor and cathode degradation in FEDs. 2Because of the small penetration depth at low voltages, the loss processes are believed to be associated with surface recombination, and thus, the surface coating and encapsulation of phosphors is an important technique to improve low-voltage cathodoluminescence (CL) and chemical stability and to reduce outgassing. Coatings can also reduce phosphor surface degradation (such as oxidation) associated with display fabrication processes thus reducing the surface dead-layer thickness and passivating surface recombination centers. Recently, Bechtel et al. reported a significant improvement in maintenance of ZnS:Ag by applying a thin calcium polyphosphate coating.3 However, this work focused on the midvoltage region (approximately 4 kV) in which the surface effect is less critical. Also, no improvement in efficiency was reported. It is the aim of this paper to present a coating technique that can improve the CL efficiency at voltages less than 2 kV by reducing surface-related losses and at the same time protect the phosphors by completely encapsulating the phosphor particles. SiO 2 was used as the coating material because of its favorable band alignment when forming a heterojunction with ZnS.4 Furthermore, SiO 2 , which consists of light elements and has low density, exhibits minimal losses in e...

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Advances in field emission displays phosphors

Cited by 165 publications

References 45 publications

Multi-Photon Phosphor Feasibility Research

Multi-Photon Phosphor Feasibility Research

Uniform and continuous Y2O3 coating on ZnS phosphors

Thin SiO₂ coating on ZnS phosphors for improved low-voltage cathodoluminescence properties

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Advances in field emission displays phosphors

Cited by 165 publications

References 45 publications

Multi-Photon Phosphor Feasibility Research

Multi-Photon Phosphor Feasibility Research

Uniform and continuous Y2O3 coating on ZnS phosphors

Thin SiO2 coating on ZnS phosphors for improved low-voltage cathodoluminescence properties

Contact Info

Product

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Thin SiO₂ coating on ZnS phosphors for improved low-voltage cathodoluminescence properties