Bridgman crystal

M. C. Liang, C. W. Fan. Three-dimensional thermocapillary and buoyancy convections and interface shape in horizontal Bridgman crystal growth. J Cryst Growth 180 5% , 1997. 

L. Davoust, R. Moreau, M. D. Cowley, P. A. Tanguy, F. Bertrand. Numerical and analytical modelling of the MHD buoyancy-driven flow in a Bridgman crystal growth configuration. J Cryst Growth 750 422, 1997. 

Mitchell (185) assigned to it the formula [irXg]- --2Ag, where Ag represents a silver ion vacancy. The complex acts as a transient electron trap. Eachus and Graves (191), from data obtained on Bridgman crystals, calculated a trap depth of 0.44 eV for the bromide complex in silver bromide. 

Fig. 1.4 An anthracene single crystal made by the Bridgman crystal-growth method, then cleaved and polished. The length of the crystal is about 2 cm and its thickness 1 cm. Along the direction of sight in this photograph, the c direction, the strong double refraction is apparent. Image provided by N. Karl [1]. Cf the coloured plates in the Appendix.

Fig. 4.5 The excitation spectrum (Ti So) of the energetically lower of the two Davydov components (14 738 cm ) of the triplet 0,0 transition in anthracene at 1.8 K in a Bridgman crystal and in a sublimation crystal. The spectral line is strongly inhomogeneously broadened in the Bridgman crystal. See Fig. 6.5.10 and Sect. 6.5.2. After [7].

Fig. 6.17 Surface excitons in anthracene, observed in the reflection spectrum, b polarised with perpendicular incidence onto the (001) surface of the crystal (the cleavage surface of a Bridgman crystal). The minima I, II and (III) (the latter with an enlarged scale in the inset) in the broad reflection of the bulk exciton are identified as excitons from the...

The solubility, diffusion, and electrical behavior of Li in GaAs were investigated by means of chemical analysis, conductivity, and Hall-effect measurements. Both floating-zone and Bridgman crystals were examined. The diffusion was non-ideal and obeyed ... 

Systematical steps towards exact stoichiometric and uncompensated CdTe Bridgman crystals ,... 

Bridgman crystals contain several major grains and numerous subgrains within each major grain. A Berg-Barrett X-ray topography study of Bridgman material... 

Application of ACRT opened up a large number of possible parameter combinations. Quenching studies of crystals grown under a wide variety of conditions showed interface depths of mm for x = 0.12 and 0.19 start crystals, unlike the values of 1 and 4 mm, respectively, seen in equivalent standard Bridgman crystals. 

All static studies at pressures beyond 25 GPa are done with diamond-anvil cells conceived independently by Jamieson [32] and by Weir etal [33]. In these variants of Bridgman s design, the anvils are single-crystal gem-quality diamonds, the hardest known material, truncated with small flat faces (culets) usually less than 0.5 nun in diameter. Diamond anvils with 50 pm diameter or smaller culets can generate pressures to about 500 GPa, the highest static laboratory pressures equivalent to the pressure at the centre of the Earth. 

TJItrahigh (99.999 + %) purity tellurium is prepared by zone refining in a hydrogen or inert-gas atmosphere. Single crystals of tellurium, tellurium alloys, and metal teUurides are grown by the Bridgman and Czochralski methods (see Semiconductors). 

Research. A significant impact on research at high pressure has come about with the use of gem quaHty diamonds as Bridgman-type anvils in a smaU compact high pressure device (40—42). With this type of apparatus, pressures greater than those at the center of the earth (360 GPa = 3.6 Mbars) have been reached, and phase transformations of many materials have been studied. Because of the x-ray transparency of diamond, it is possible to determine the stmcture of the phases under pressure. Because of the strenuous environment, crystals selected for this appHcation have to be of very high quaHty. 

In Bridgman growth [155], a boat or vessel filled with the melt is slowly cooled from one side, so that the crystal forms from that side. In Czochralski growth [156,157] a cylindrical crystal sits on the surface of the melt and is slowly pulled upward. In both cases the hydrodynamical flow of the melt is an important factor in the chemical composition and fine structure of the resulting crystal. 

Y. Y. Khine, J. S. Walker. Thermoelectric magnetohydrodynamic effects during Bridgman semiconductor crystal growth with a uniform axial magnetic field. J Cryst Growth 7 5 150, 1998. 

Top Bridgman procedure for the production of large single crystals. From a eutectic melt one can obtain a single crystal with embedded wires. Bottom possible subsequent steps of processing... 

Related methods include the Bridgman and Stockbarger methods where a temperature gradient is maintained across a melt so that crystallization starts at the cooler end this can either be achieved using a furnace with a temperature gradient or by pulling the sample through a furnace. 

Figure 3.6 Methods for crystal growth from melt (a) Czochralski method (b) Kyropoulos method (c) Bridgman-Stockbarger method and (d) Vemeuil method.

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