Transfer of Energy Between Centres in Zinc Sulphide Phosphors

Klasens, H. A.

doi:10.1038/158306c0

Cited by 129 publications

(41 citation statements)

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“…At high frequencies or low temperatures equilibrium will not be attained, and the relative capture cross sections of the centers will cause preferential activation of the blue centers and consequent blue emission. This behavior is similar to hole-migration-based explanations of color changes with temperature and excitation conditions proposed by Schon, 24 Klasens, 25 and others.…”

Section: B Relaxation; Temperature Effectssupporting

confidence: 71%

Electroluminescence in Zinc Sulfide

Gillson

Darnell

1962

Phys. Rev.

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Microscopic observations of electroluminescent emission from ZnS crystals activated with Cu, Cu :Pb, or Ag have shown that the typical emitting entity is a narrow line. These lines lie in directions of the wurtzite structure in planar regions associated with stacking faults or closely spaced alternations in crystai structure. A model of electroluminescence involving linear physical defects is proposed for the origin of the lines and their observed dependence on voltage, frequency, and phase of the applied electric field.

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Section: B Relaxation; Temperature Effectssupporting

confidence: 71%

Electroluminescence in Zinc Sulfide

Gillson

Darnell

1962

Phys. Rev.

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“…As the temperature increases, more and more holes are transferred to the red centers. This transfer is at the expense of the blue emission and depends on the temperature in an exponential manner, exp (--Eq/kT), as discussed by Klasens (15).…”

Section: El Intensity As a Function Ofmentioning

confidence: 97%

“…The electron in the conduction band may return to a blue center, giving rise to blue emission, or be captured by another Fe 3+ center. 15 Since the blue emission decreases rapidly with increasing Fe concentration, it is apparent that the Fe center has the larger hole capture cross section.…”

Section: El Intensity As a Function Ofmentioning

confidence: 99%

Iron Activated ZnS Phosphors

Jaffe

Banks

1964

J. Electrochem. Soc.

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Iron can serve as an activator in ZnS phosphors, giving a 660 m~-peaked red emission. Previous difficulties with the preparation of reproducible samples are overcome with the use of C1, Br, I, A1, Ga, or In coactivators. The red emission is always accompanied by a 460 m~ blue emission attributed to Cu impurity and/or (more likely) to Zn vacancies. Detailed luminescence characteristics of ZnS: Fe,I phosphors under ultraviolet (u.v.) and EL excitation are presented. A model of the Fe center showing the transitions leading to luminescence and killing, which may occur in the same center, is given.The killing effect of iron, cobalt, and nickel on the luminescence of ZnS phosphors is well known. Less known are their intensification effects (1-4). In several cases both killing and intensification are present simultaneously depending on the particular combination and concentration of activator [Cu, Au (2,3) or Ag (4)] and killer. In addition to killer and intensifier action, there are also reports of iron (4-7), cobalt (4, 8), and nickel (4) acting as true activators, i.e., originators of luminescence, having red and near and far infrared emission, respectively.Because these phosphors have weak emissions and are difficult to reproduce no previous detailed study has been reported. In the case of ZnS: Fe phosphors, it has been found that the use of coactivators (C1, Br, I, AI, Ga, or In) resulted in reproducible samples. This, coupled with the use of modern instruments, allows a study of the ZnS:Fe system to be made.The Fe activated phosphors were studied under cathode-ray, u.v. (365 n~) and a-c field (EL) excitation, but the cathodoluminescence will not be reported here since it was similar to the photoluminescence. Phosphor PreparationPhosphors were prepared from RCA ZnS (33Z19). Iron, Cu (when used to make EL phosphors) and halogens were added from stock solutions of the nitrate, sulfate, and ammonium salts, respectively. A1 was added as a solution of NH4Al(SO4)2, and Ga and In were added as the sesquisulfides. 3"4 After addition of the appropriate amounts of the components, the raw mixes were slurried and dried at ll0~The dried powders were remixed and placed in a loosely capped silica test tube which was then put into a larger silica firing tube having one end closed and a gas inlet and outlet at the other end.

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“…Abrupt and tunable quenching of PL is rarely reported. In early works on phosphors, Klasens [11], Garlick and Gibson [12], and Vergunas and Gavrilov [13], described this unusual behavior of PL in ZnS. The behavior was explained by Klasens [14] who suggested a two-center model.…”

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confidence: 97%

Tunable thermal quenching of photoluminescence in GaN

Reshchikov

McNamara

2014

Phys. Status Solidi C

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In this work, we report the observation of abrupt and tunable thermal quenching of photoluminescence (PL) in high‐resistivity, undoped GaN. The ultraviolet luminescence (UVL) band in these samples exhibited abrupt and tunable quenching, which is similar to behavior observed for p ‐type GaN:Mg samples. Such behavior has never been observed for undoped GaN and was very rarely reported for other semiconductors. We describe the effect of temperature and excitation intensity on PL in undoped GaN with a phenomenological model involving three defect species. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Transfer of Energy Between Centres in Zinc Sulphide Phosphors

Cited by 129 publications

References 1 publication

Electroluminescence in Zinc Sulfide

Electroluminescence in Zinc Sulfide

Iron Activated ZnS Phosphors

Tunable thermal quenching of photoluminescence in GaN

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