Modified method of conversion of CdF<sub>2</sub>into a semiconductor

Wojciechowski, Jason; Kamińska, E.

doi:10.1088/0022-3727/12/12/003

Cited by 11 publications

(5 citation statements)

References 4 publications

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“…The details on the crystal growth have been reported elsewhere 1131. Samples singly doped with Pr, Sm, Eu, Tb, Dy, Er and doubly doped with Eu and Er were studied before and after annealing at 750 K in hydrogen atmosphere [14]. We report here only the results concerning Sm, Eu, and Er.…”

Section: Methodsmentioning

confidence: 99%

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Jouart

Bissieux

Mary

et al. 1985

Physica Status Solidi (b)

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It is shown that, under visible or near infrared excitation, the Eu2+ ion sensitizes the [RE3+, Fr] fluorescence in as-grown and annealed CdF, crystals (RE = Sm, Eu, Er) cooled a t 77 K and previously irradiated with UV light. Non-radiative energy transfer from Eu2+ in cubic surroundings to minor [RE3+, F;] [RE3+, F,], via la bande de conduction du rBseau h&e, est identifi6. Le mecanisme de sensibilisation est fond6 sur la photoionisation des EuZ+, il requiert la presence simultanee de fluors interstitiels neutres (FP), chacnn associ6 avec un RE3+. Cette Btude permet d'etablir l'existence de trois types d'ions F; dans CdF,. A partir du spectre d'excitation de la fluorescence, une valeur (1,l eV) de 1'Bnergie du seuil de photoionization des ions E u~+ dans CdF, est obtenue, en bon accord avec le modltle de Pedrini et al. En outre, la spectroscopie de fluorescence de l'ion Eu3+ est utilisBe pour prBciser la sym6trie du site occupe par l'ion E u~+ .

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Section: Methodsmentioning

confidence: 99%

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Jouart

Bissieux

Mary

et al. 1985

Physica Status Solidi (b)

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“…In some cases it is possible, however, to obtain n-type semiconducting properties by doping, for example, in CdF 2 (Y). 207 Exceptional metallic conductivity is observed in the metal-rich compound Ag 2 F, 208 even superconductivity in Hg 3−δ AsF 6 209 -despite the presence of fluoride. Mixed-valence silver fluorides have been recently discussed as possible candidates for superconductivity.…”

Section: Electrical Conductivitymentioning

confidence: 99%

Fluorides: Solid‐State Chemistry

Massa¹

2005

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Inorganic solid fluorides and fluorometalates play a unique role in inorganic chemistry. The preparation, mostly using aqueous or anhydrous HF or even elemental F 2 , requires special conditions: no glass or silicate containing vessels can be used. Their structural chemistry is governed by the outsider role of the fluoride anion. It is the smallest and least polarizable anion and its mainly ionic compounds follow the rules of hard spheres packing better than any other class of substances. Nearly all metal ions except those with the largest ionic radii form fluoride structures with octahedral [M n + F 6 ] (6− n )– units. If the metal:fluorine ratio is less than 6, these octahedra share common vertices or, in rare cases, edges or even faces to account for electroneutrality, the more the lower the oxidation state of the metal. In this way, a variety of 1D chain, 2D net, and 3D framework structures is formed that can be classified into a few large structure families. In binary fluorides, for example, VF 5 has an octahedral cis‐chain structure, VF 4 a layer structure based on a square net of corner‐connected octahedra, VF 3 has a ReO 3 ‐related 3D structure with all corners of octahedra connected, and VF 2 has the rutile‐type structure with partial edge‐sharing of octahedra. In ternary or quaternary compounds, for example, alkali or alkaline earth fluorometalates, the same principles are valid for the anionic substructure while the counter cations fill interstices and stabilize at the same time the structure. The main structure families are grouped according to the basic principles of octahedral nets. These are the ReO 3 ‐related trifluorides, the fluoride perovskites AMF 3 , their relatives elpasolites A 2 A′MF 6 , and cryolites A 3 MF 6 , as well as some layer structures with square nets. A second large family is based on mixed octahedral nets including triple units: it includes for example, the pyrochlores, the weberites, the hexagonal and tetragonal tungsten bronze structures, and some derivable layer structures. Recent developments deal with ‘tailoring’ of low‐dimensional or framework structures using ‘soft‐chemistry’ methods. The relatively simple structural chemistry of fluorides invoked their use as model systems, for instance, for the investigation of electronic effects like Jahn–Teller ordering, or for magnetic investigations. Besides the cryolite Na 3 AlF 6 used in Al production, some fluorides are of technical interest owing to their special optical properties (e.g. laser optics, fluoride glasses), their ability for fluoride ion conductivity, or their role as catalysts for fluorinations or halogene exchange in organic systems.

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“…This method presents only a poor reproducibility and results in stress and even cracks of the samples, so that other ways of preparing conducting crystals are useful. Methods for conversion from the insulator to the semiconducting state have been proposed, relying on the reduction effects of liquid Sn or I n [GI or of hydrogen [7].…”

Section: Introductionmentioning

confidence: 99%

Growth of Semiconducting CdF₂:Ho³⁺ Crystals and Study of Their Optical and Transport Properties

Pouradier¹,

Grimouille²

1981

Physica Status Solidi (b)

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A method for growing CdF,:Ln3+ crystals (Ln lanthanide) is presented which results in semiconducting samples without any subsequent annealing. It is found that the main preparation parameters act on the optical and transport properties through a common parameter E,. The infra-red absorption of the samples as well as their conductivity are then analysed in the frame of a model with impurity-banding and hopping conductivity, resulting in informations on the impurity density of states.Nous prhsentons une m6thode de cristallogknbse de CdF, : Ln3+ semiconducteur (Ln Lanthanide), ne nkcessitant pas de recuit du mat6riau. On montre que les principaux parametres de prkparation agissent sur les proprikt6s optiques e t de transport par le jeu d'un parametre commun E,. L'absorption infra-rouge et la conductivith des kchantillons sont alors analys6es dans le cadre d'un modble avec bande d'impuretks e t conduction par sauts. Des informations sont obtenues sur la densit6 d'6tats d'impureths.

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Modified method of conversion of CdF₂into a semiconductor

Abstract: A modified method of conversion of CdF2 is described, based on heating CdF2 crystals in a hydrogen atmosphere. Proper choice of temperature and heating time enables one to obtain CdF2 crystals within a broad range of resistivities, the lowest value being of about 0.3 Omega cm.

Cited by 11 publications

References 4 publications

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Fluorides: Solid‐State Chemistry

Growth of Semiconducting CdF₂:Ho³⁺ Crystals and Study of Their Optical and Transport Properties

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Modified method of conversion of CdF2into a semiconductor

Abstract: A modified method of conversion of CdF2 is described, based on heating CdF2 crystals in a hydrogen atmosphere. Proper choice of temperature and heating time enables one to obtain CdF2 crystals within a broad range of resistivities, the lowest value being of about 0.3 Omega cm.

Cited by 11 publications

References 4 publications

Study of the Sensitization Effect of Eu2+ Ions on the Trivalent Rare‐Earth Fluorescence in CdF2 Crystals

Study of the Sensitization Effect of Eu2+ Ions on the Trivalent Rare‐Earth Fluorescence in CdF2 Crystals

Fluorides: Solid‐State Chemistry

Growth of Semiconducting CdF2:Ho3+ Crystals and Study of Their Optical and Transport Properties

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Product

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Modified method of conversion of CdF₂into a semiconductor

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Study of the Sensitization Effect of Eu²⁺ Ions on the Trivalent Rare‐Earth Fluorescence in CdF₂ Crystals

Growth of Semiconducting CdF₂:Ho³⁺ Crystals and Study of Their Optical and Transport Properties