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Vertical Bridgman Method (vertical + bridgman_method)
Selected AbstractsInvestigation on growth defects in Pb(Zn1/3Nb2/3)O3 -PbTiO3 crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2006Min Jin Abstract Relaxor ferroelectric crystal (1-x)Pb(Zn1/3Nb2/3)O3 -xPbTiO3 (PZNT) with x=0.07 (PZNT93/7) has been grown by the vertical Bridgman method from the high temperature solution of PZNT-PbO system. The growth defects, such as nucleation core, inclusions, boundaries and particles, were investigated by optical microscope and scanning electron microscope. Sub-structures were found in the flux inclusions and the lack of ZnO component in PZNT crystals was attributed to the existence of ZnO particles in the inclusions. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Luminescence properties and growth of pure and anthracene-doped naphthalene crystalsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2007N. Balamurugan Abstract Pure and anthracene-doped naphthalene crystals of high quality with 20 mm diameter and 60 mm length have been grown by the self-seeded vertical Bridgman method. The powder X-ray diffraction studies and the Raman analysis show that the guest molecules appear as defects in the form of irregularly oriented molecules that do not significantly distort the monoclinic structure. The absorbance and fluorescence studies show high Stoke's shift for anthracene-doped naphthalene crystals. From this we deduce that the exciting wavelength of the light (270 nm) is completely absorbed by the naphthalene, so that fluorescence from anthracene takes place as a result of energy transfer from naphthalene. The decay time observed for anthracene-doped naphthalene is 27 ± 2 ns. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of variable crucible dropping rate on solid-liquid interface in CdZnTe crystal growthPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2010Chenying Zhou Abstract The Cd0.9Zn0.1Te crystal growth with low pressure and vertical Bridgman method (LPVB) was numerically simulated and analysed by the simulation software of Comsol Multiphysics. In the process of crystal growth, the influence of variable crucible dropping rate on solid-liquid interface was studied in this paper. The variability of crucible dropping rate was achieved by a specifical furnace temperature distribution function, while the selection and analysis of crucible dropping rate was obtained by the combination of orthogonal experimental design method and regression analysis method. In this paper, the value of relative crystal growth rate was defined, and the influence of variable crucible dropping rate on solid-liquid interface was discussed by comparing these values. The simulation results showed that if the crucible dropping rate was 3.5 mm/h (,1) in the first stage and 0.6 mm/h (,2) in the second stage, and the distance (d) between the bottom of crucible and the position of melting point in tempreture field was 0.02 m at the time of dropping rate change, the solid-liquid interface was appreciably convex after 211 hours' growth, and the relative crystal growth rate was 0.45%, which made the solid-liquid interface smooth and kept the crystal grow up spontaneously. [source] Vertical Bridgman growth and annealing effect of Bi doped ZnSe single crystalPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2004C. B. Oh Abstract In order to prepare p-type ZnSe, bismuth (Bi) as an acceptor dopant was doped into ZnSe single crystal by vertical Bridgman method. Photoluminescence (PL) spectra measured at 4.2 K on as-grown crystal showed the strong shallow donor,acceptor pair (DsAP) emission, deep donor,acceptor pair (DdAP) emission and weak I1Bi emission line. To enhance the activation ratio of Bi in ZnSe single crystals, ZnSe:Bi was annealed in saturated zinc and selenium atmosphere at different temperatures. In the case of annealing in the range of 700,800 °C, DdAP emission disappeared and the intensities of DsAP and I1Bi emission relatively increased. From the dependence of PL spectra on excitation light intensity and the temperature, the acceptor activation energy and deep donor level were estimated about 103 meV and 34 meV, respectively. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||