Growth and properties of beryllium oxide single crystals

Austerman, S.B.

doi:10.1016/0022-3115(64)90182-5

Cited by 51 publications

(8 citation statements)

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“…Similar defects in BeO single crystals have been observed by the authors in [8,15,22]; here it has been established that with low solidification temperatures (<1323 K) in melts of Li 2 MO 4 : 1.25 MO 3 in BeO crystals a considerable number of small isolated pores develop, that sometimes give crystals an opaque form.…”

supporting

confidence: 55%

“…BeO single crystals, grown from solution in a melt, where as a solvent there was use of Li 2 MoO 4 :MoO 3 and Li 2 MoO 4 :WO 3 as a rule had twins, they contain several dislocations and exhibit well-developed boundaries [8,14,20]. The BeO single crystals obtained by a hydrothermal method have so far not been studied sufficiently, and the main methods for BeO single crystal preparation are solidification from the gas phase and from a solution in a melt.…”

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confidence: 99%

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Single crystals and light-transmitting BeO-ceramic for electronic technology

et al. 2010

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Problems are discussed for the preparation and physicochemical properties of beryllium oxide and light-transmitting BeO-ceramic as promising materials for electronic technology.Ceramics and single crystals of beryllium oxide (BeO) are distinguished from other alkali-earth metal oxides by high refractoriness and melting temperature (~2750 K) [1,2], and they are considered [3] as promising materials for quantum electronics. It is well known that BeO is a good dielectric material with a broad forbidden zone (~10.8 eV), it exhibits high chemical, radiation resistance, and thermal conductivity, that for ceramic BeO specimens is (at room temperature) 250 -320 W/(m·K) [2,4]; for BeO single crystals compared with ceramic based on BeO the thermal conductivity is somewhat higher.Currently powerful laser radiation in the ultraviolet (UV) and vacuum ultraviolet (VUV) regions of the spectrum is practically realized by means of gas lasers in gases of hydrogen, fluorine, nitrogen, in excimers, and exiplex mixtures [5]. Up until now no quantum generators have been created in the UV and VUV regions of the spectrum based on broad zone high-temperature oxides Al 2 O 3 , MgO and BeO.Beryllium oxide is of considerable interest as a working body for quantum electronic instruments, and also reradiators and optical systems of the UV and VUV ranges of the spectrum [2, 3]. Currently powerful coherent radiation in the UV and VUV regions of the spectrum may find practical application in the production of electronic instruments as radiation sources and excitation in photolithography, photoluminescence, photochemistry, biology, in space studies and photonics.With use of beryllium oxide single crystals and lighttransmitting BeO-ceramic as active media for lasers it is necessary to obtain high purity crystals, in order that during radiation there are no discoloration centers and the crystals exhibit photochemical stability. For BeO there is a typical minimum number of crystal lattice defects. In addition, BeO exhibits low isomorphous compatibility (at the level of 10 -3 -10 -5 wt.%), that makes stepwise ionization of active impurity centers hardly probable. It is well known that BeO-ceramic during excitation with X-radiation and electrons exhibits two peak luminescence peaks in the UV and VUV regions of the spectrum with maxima of 4.9 -5.0 and 6.7 eV [2], excited the edge of fundamental absorption. All of this makes it possible to consider BeO promising as a material for solid lasers of the UV and VUV regions of the spectrum. In view of this development of technology for preparing optically improved single crystals and ceramics based on BeO with special physicochemical properties, making it possible to provide the required spectral-energy and spatial characteristics, is of particular interest.In this work problems are discussed of preparing and the physicochemical properties of beryllium oxide single crystals and light-transmitting BeO-ceramic as promising materials for electronic technology. Creation of solid active materials based on single c...

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confidence: 99%

Single crystals and light-transmitting BeO-ceramic for electronic technology

et al. 2010

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“…The crystal studied was grown from LizMoO4-MoO3 (Austerman, 1964) ing several percent LiPO3 as an added impurity at a temperature of approximately ll00°C. For identification of stacking faults, the following distinctive features of stacking-fault images were examined: (1) The defects are two-dimensional defects on the basal plane; (2) Stacking-fault images show the typical fringe pattern in so-called section topographs (Kato, Usami & Katagawa, 1967;Authier & Sauvage, 1966;Authier, 1968;Chikawa & Austerman, 1968); (3) Stackingfault images must disappear for the reflections that satisfy h. f= n (n = 0 or integer) where h is the reciprocal-lattice vector and f is the fault vector (Whelan & Hirsch, 1957).…”

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Stacking faults in BeO crystals

Chikawa¹,

Austermann²

1974

J Appl Cryst

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A complex stacking-fault structure was revealed in a flux-grown BeO crystal, with X-ray topographic images as well as characteristic interference fringes around the stacking-fault image. Coplanar with the stacking fault are a number of dislocations of various (unidentified) Burgers vectors, all probably having a common origin during crystal growth.The crystal structure of ~-beryilia is hexagonal closestpacked (wurtzite type) at room temperature. The hightemperature form (fl-beryllia) is tetragonal (Smith, Cline & Austerman, 1965). Evidence for the presence ofacubic form has not been reported. Therefore, the stackingfault energy for BeO seems to be high and stacking faults ha,re not been found in BeO crystals. The purpose of the present note is to give evidence of stacking faults in ~-beryllia.The stacking faults were observed by X-ray diffraction topography. The crystal studied was grown from LizMoO4-MoO3 (Austerman, 1964)

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“…A flux-grown BeO crystal (Austerman, 1964) with an inversion twin boundary parallel to the c axis was used. On the basis of Lang topographs, this crystal was selected from others as being nearly entirely free of strain regions.…”

Section: Comparison Of Theory and Experimentsmentioning

confidence: 99%

“…Flux-grown BeO crystals commonly are twinned, whereby the two components of the twin have opposite senses of the polar axes. The twin structure was found in BeO crystals by Austerman (1962), and has been formally described (Blank, Delavignette, Gevers & Amelinckx, 1964;Newkirk & Smith, 1964;Austerman & Gehman, 1966) and has been designated as the 'inversion twin' (Austerman & Gehman, 1966). The wurtzite structure can be considered as a hexagonally close packed stacking of A atoms with the other B atoms in tetrahedral interstices.…”

Section: Introductionmentioning

confidence: 99%

X-ray diffraction contrast of inversion twin boundaries in BeO crystals

Chikawa¹,

Austerman²

1968

J Appl Cryst

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Inversion twin boundaries in BeO crystals (wurtzite structure) can be studied by X-ray topography. They can be regarded as a special kind of stacking fault. The section topograph images of a twin boundary, lying parallel to the c axis, agree well with the theory for a single stacking fault. From the contrast variation of the images for various reflections, it is concluded that the oxygen sublattice on one side of the twin boundary is displaced from that on the other side by 1(1/16)[00111 so that the oxygen layer parallel to the basal plane on one side is located at the center of the oxygen and beryllium layers on the other side. The image contrast in section topographs is very sensitive to the phase shift due to a fault. The phase shift of a few degrees can be detected easily. This sensitivity leads to an accurate structure determination of the inversion twin boundary.

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Growth and properties of beryllium oxide single crystals

Cited by 51 publications

References 3 publications

Single crystals and light-transmitting BeO-ceramic for electronic technology

Single crystals and light-transmitting BeO-ceramic for electronic technology

Stacking faults in BeO crystals

X-ray diffraction contrast of inversion twin boundaries in BeO crystals

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