Studies on Growth and Characterization of High Quality Metal Oxide Single Crystals

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High quality metal oxide single crystals have been applied to many electronic devices. This study is to clarify the growth and characterization of rutile and trirutile single crystals by floating zone method, and also quartz single crystals by hydrothermal method. Following results were obtained through this investigation.(1) Rutile single crystals free from low-angle grain boundaries were grown with the addition of Al, Zr and Sc. Optical quality of the crystals was superior to that of commercially available crystals grown by the Verneuil method.(2) MgTa_2O_6 single crystals which has trirutile structure were successfully grown by FZ method. The refractive indices for ordinary and extraordinary rays were 2.07 and 2.18 under white light, respectively, and birefringence was 0.11. Pale green NiTa_2O_6 single crystals were also grown by the same method. The crystals had strong absorption spectra in the wave length ranges of 300-500,650-900 and 1100-1600 nm.(3) Quartz single crystals were grown from ammonium fluoride solutions at 230-280 ﾟC and 4-100 MPa under hydrothermal condition. The maximum growth rate of the Z face attained 0.88 mm/day which was comparable to that in alkaline solutions. The linear defect density in Z growth zone was about 10^3-10^5 pcs/cm^2, higher than that alkaline solutions. Strong absorption at about 3500cm^<-1> by -OH streching vibration was observed in FTIR spectra.