Dysprosium-doped orthorhombic yttrium aluminate(Dy:YAlO3or Dy:YAP)single crystals were grown by the Czochralski method with a size ofΦ43 mm×150 mm.Based on the measurements of spectra and theoretical analysis,th...Dysprosium-doped orthorhombic yttrium aluminate(Dy:YAlO3or Dy:YAP)single crystals were grown by the Czochralski method with a size ofΦ43 mm×150 mm.Based on the measurements of spectra and theoretical analysis,the white-light emission was investigated with different doping concentrations.The optimal white emission was achieved at Dy^(3+)doping concentration of 1.0%under 450 nm excitation.Combining with residual pumping light,the white-light output was successfully obtained with Commission Internationale de l'Eclairage(CIE)coordinates x=0.3797,y=0.3685,the color temperature of 4000 K,and the largest fluorescence quantum yield of 46.9%.With the development of the GaN laser diode,the Dy:YAP single crystal has proven applicable in white-light-emitting diodes.展开更多
Potassium tantalate niobate （KTa1-xNbxO3, KTN） crystals with different dimensions and quality situations were grown by Czochralski method. Crystal growth process and morphology properties of KTN are presented in thi...Potassium tantalate niobate （KTa1-xNbxO3, KTN） crystals with different dimensions and quality situations were grown by Czochralski method. Crystal growth process and morphology properties of KTN are presented in this paper. It was found that some defects, such as bubble, inclusion, crack, dislocation etc., can all appear if the crystal is grown in an improper condition. The character and formation mechanism of such defects in macro growth are discussed. We consider that the CO2, which was not released absolutely during the sintering process and dissolved in the melt, led to bubbles. The composition of the inclusion caused by high pulling and rotation rates is KTN polycrystalline. The crack and dislocation in KTN crystal mainly come from improper temperature field. Etching and high-resolution X-ray diffraction （HRXRD） experiment results indicate that the central area is the defects concentrated.展开更多
By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （...By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92163207,52002272,61835014,51890860,51890864,and 51890865)。
文摘Dysprosium-doped orthorhombic yttrium aluminate(Dy:YAlO3or Dy:YAP)single crystals were grown by the Czochralski method with a size ofΦ43 mm×150 mm.Based on the measurements of spectra and theoretical analysis,the white-light emission was investigated with different doping concentrations.The optimal white emission was achieved at Dy^(3+)doping concentration of 1.0%under 450 nm excitation.Combining with residual pumping light,the white-light output was successfully obtained with Commission Internationale de l'Eclairage(CIE)coordinates x=0.3797,y=0.3685,the color temperature of 4000 K,and the largest fluorescence quantum yield of 46.9%.With the development of the GaN laser diode,the Dy:YAP single crystal has proven applicable in white-light-emitting diodes.
文摘Potassium tantalate niobate （KTa1-xNbxO3, KTN） crystals with different dimensions and quality situations were grown by Czochralski method. Crystal growth process and morphology properties of KTN are presented in this paper. It was found that some defects, such as bubble, inclusion, crack, dislocation etc., can all appear if the crystal is grown in an improper condition. The character and formation mechanism of such defects in macro growth are discussed. We consider that the CO2, which was not released absolutely during the sintering process and dissolved in the melt, led to bubbles. The composition of the inclusion caused by high pulling and rotation rates is KTN polycrystalline. The crack and dislocation in KTN crystal mainly come from improper temperature field. Etching and high-resolution X-ray diffraction （HRXRD） experiment results indicate that the central area is the defects concentrated.
基金supported by the National Natural Science Foundation of China (50590401)
文摘By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.
