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The 14 mm x 12 mm AlN single crystal is synthesized by the homoepitaxial physical vapor transport method. The crystal sample sliced from the boule is processed by lapping and chemical mechanical processes (CMP). The sample is characterized by Raman spectrometer, high resolution X-ray diffractometer, X-ray photoelectron spectrometer and photoluminescence spectrometer. The Raman results show that the full width at half maximum (FWHM) of the E2 (high) phonon mode of Raman spectrum is 3.3 cm-1 in the central region of the sample, and the FWHM of the E2 (high) phonon mode of Raman spectrum is 4. 3 cm-1 in the edge of the sample, the AlN single crystal exhibits high crystal quality. The FWHM of the X-ray rocking curve increase to 100" in the central region of the homoepitaxial growth crystal, while the FWHM of the X-ray rocking curve is 205" in the edge region of the homoepitaxial growth crystal, which indicates defects exist in the crystal. XPS results show that there are C, O, Si impurity elements in the crystal, and the atomic concentration of the impurities is 0.74%, 1.43% and 2.14%, respectively. It is found that the mainly oxygen impurities exist in the crystal in the form of Al--O, N--Al--O bonding. PL spectra show that crystal contains VAl-ON compound defect and VAl point defect. [ABSTRACT FROM AUTHOR]

As a kind of excellent host material for solid-state lasers, GdScO3 crystal has attracted more and more attention. In this paper, Yb,Ho∶GdScO3 crystal with the size of ϕ30 mm × 50 mm was firstly grown by Czochralski growth method. The powder diffraction data were obtained by X-ray diffraction, and the structure parameters were fitted by GSAS software. Raman spectra were measured. In the range of 100 to 700 cm-1, there are 18 Raman vibration peaks were observed. The spectral properties including transmission and emission of Yb,Ho∶ GdScO3 crystal were characterized. The center of the strongest absorption band is at 975 nm, which comes from the transition of Yb3 + ∶2 F7/2 →2 F5/2. The absorption cross section of Yb3 + were calculated and the values at 940, 975 nm are 0. 31 × 10 -20 and 0. 42 × 10 -20 cm2. The transition intensity parameter (Ωt) of Ho3 + was calculated by Judd-Ofelt theory, Ω4 / Ω6 is 2. 04. And spectral parameters such as radiation transition probability, energy level lifetime and fluorescence branching ratio were calculated. The results show that Yb,Ho∶GdScO3 is a promising candidate material for 2 ~3 μm laser crystals because of its excellent luminescence properties. [ABSTRACT FROM AUTHOR]