The influence of Er3+ ions on the spectra of Yb^(3+),Er^(3+): Sc_2 SiO_5(SSO) single crystal, which was obtained by Czochralski(Cz) method, is discussed. The absorption coefficient at 980 nm was 13.36 cm^(-1) with a p...The influence of Er3+ ions on the spectra of Yb^(3+),Er^(3+): Sc_2 SiO_5(SSO) single crystal, which was obtained by Czochralski(Cz) method, is discussed. The absorption coefficient at 980 nm was 13.36 cm^(-1) with a peak absorption cross-section of 1.46 × 10^(-20) cm2. The emission cross-sections at 1034 nm and 1062 nm were 5.5 × 10^(-21) cm^2 and4.9 × 10^(-21) cm^2, respectively. The fluorescence lifetime was estimated as 1.24 ms at 1061 nm. The mechanical properties of SSO single crystal were also presented.展开更多
Ta5+doped β-Ga2O3 single crystals were grown by using the optical floating zone method, and then annealed in the air and nitrogen gas at 1400℃ for 20 hours.The transmittance spectra, photoluminescence(PL), x-ray irr...Ta5+doped β-Ga2O3 single crystals were grown by using the optical floating zone method, and then annealed in the air and nitrogen gas at 1400℃ for 20 hours.The transmittance spectra, photoluminescence(PL), x-ray irradiation spectra, and PL decay profiles of the samples were measured at room temperature.The relevant results show that the optical transmittance of the samples annealed in the air or nitrogen gas was improved.By drawing the(ahv)2–hv graph,it can be seen that the band gap decreased after being annealed in the air, but increased in nitrogen gas.The PL spectra and x-ray irradiation spectra show that the luminescent intensity of the sample annealed in the air increased substantially,while decreased for the sample annealed in nitrogen.The PL decay time of the Ta:β-Ga2O3 annealed in the air increased significantly compared with that of the Ta:β-Ga2O3 sample without annealing, but the tendency after annealing in nitrogen gas was opposite.展开更多
Sb-doped β-Ga_(2)O_(3) crystals were grown using the optical floating zone(OFZ) method.X-ray diffraction data and X-ray rocking curves were obtained,and the results revealed that the Sb-doped single crystals were of ...Sb-doped β-Ga_(2)O_(3) crystals were grown using the optical floating zone(OFZ) method.X-ray diffraction data and X-ray rocking curves were obtained,and the results revealed that the Sb-doped single crystals were of high quality.Raman spectra revealed that Sb substituted Ga mainly in the octahedral lattice.The carrier concentration of the Sb-doped single crystals increased from 9.55 × 10^(16) to 8.10 × 10^(18) cm^(-3),the electronic mobility depicted a decreasing trend from 153.1 to108.7 cm~2·V^(-1)·s^(-1),and the electrical resistivity varied from 0.603 to 0.017 Ω·cm with the increasing Sb doping concentration.The un-doped and Sb-doped β-Ga_(2)O_(3) crystals exhibited good light transmittance in the visible region;however,the evident decrease in the infrared region was caused by increase in the carrier concentration.The Sb-doped β-Ga_(2)O_(3) single crystals had high transmittance in the UV region as well,and the cutoff edge appeared at 258 nm.展开更多
A highly transparent Eu^(3+)-doped CaGdAlO_4(CGA) single crystal is grown by the floating zone method.The segregation coefficient,x ray diffraction,and x ray rocking curve are detected,and the results reveal that the ...A highly transparent Eu^(3+)-doped CaGdAlO_4(CGA) single crystal is grown by the floating zone method.The segregation coefficient,x ray diffraction,and x ray rocking curve are detected,and the results reveal that the single crystal is of high quality.The f –f transitions of Eu^(3+) in the host lattice are discussed.The ~5D_0–~7F_2 emission transition at 621 nm(red light) is dominant over the ~5D_0–~7F_1 emission transitions at 591 and 599 nm(orange light),agreeing well with the random crystal environment of Eu^(3+) ions in a CGA crystal.The decay time of Eu:~5D_0 is measured to be 1.02 ms.All the results show that the Eu:CGA crystal has good optical characterization and promises to be an excellent red-fluorescence material.展开更多
YAG-Ce,Nd,and Yb phosphors with a triple-doped system are prepared by conventional solid-state reaction method.The fluorescence emission and excitation spectra are measured and analyzed.The influences of Yb3+ doping c...YAG-Ce,Nd,and Yb phosphors with a triple-doped system are prepared by conventional solid-state reaction method.The fluorescence emission and excitation spectra are measured and analyzed.The influences of Yb3+ doping concentration on the emission of Yb3+ and Nd3+ in YAG-Ce,Nd,and Yb are studied.The fluorescence decay spectra,lifetime,and energy transfer efficiency of Ce3+ in different host materials of YAG-Ce and Yb,and YAG-Ce,Nd,and Yb are also compared.Furthermore,the trends of fluorescence decay spectra and the lifetimes of Nd3+ and Yb 3+ in YAG-Ce,Nd,and Yb with the increase of Yb3+ concentration are discussed.Results indicate that YAG-Ce,Nd,and Yb are good candidates for downconverting phosphor,with energy transfer efficiency reaching as high as 82.8%.展开更多
V-doped MgAl6O10 is grown by the conventional Czochralski method. The crystal structure and the cell parameters are analyzed through X-ray diffraction experiments. The absorption and emission spectra are investigated....V-doped MgAl6O10 is grown by the conventional Czochralski method. The crystal structure and the cell parameters are analyzed through X-ray diffraction experiments. The absorption and emission spectra are investigated. Under pumping at 324 nm, the emission spectra of V-doped MgAl6O10 obtain two emission peaks at the wavelengths of 471 and 570 nm. Two emission bands of the spectra combine to produce a spectrum that is perceived as white by the naked eye. Therefore, V-doped MgAl6O10 single crystal can be applied as substrate for phosphor-free ultraviolet (UV)-white light-emitting diodes (LEDs).展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB0701002)the Joint Fund of the National Natural Science Foundation of China and China Academy of Engineering Physics(NSAF)(Grant No.U1530152)+1 种基金the National Natural Science Foundation of China(Grant Nos.91222112 and 61475177)Shanghai Rising-Star Program(B type),China(Grant No.14QB1401600)
文摘The influence of Er3+ ions on the spectra of Yb^(3+),Er^(3+): Sc_2 SiO_5(SSO) single crystal, which was obtained by Czochralski(Cz) method, is discussed. The absorption coefficient at 980 nm was 13.36 cm^(-1) with a peak absorption cross-section of 1.46 × 10^(-20) cm2. The emission cross-sections at 1034 nm and 1062 nm were 5.5 × 10^(-21) cm^2 and4.9 × 10^(-21) cm^2, respectively. The fluorescence lifetime was estimated as 1.24 ms at 1061 nm. The mechanical properties of SSO single crystal were also presented.
基金Project supported by the National Natural Science Foundation of China(Grant No.51802327)the Science and Technology Commission of Shanghai Municipality,China(Grant No.18511110500)
文摘Ta5+doped β-Ga2O3 single crystals were grown by using the optical floating zone method, and then annealed in the air and nitrogen gas at 1400℃ for 20 hours.The transmittance spectra, photoluminescence(PL), x-ray irradiation spectra, and PL decay profiles of the samples were measured at room temperature.The relevant results show that the optical transmittance of the samples annealed in the air or nitrogen gas was improved.By drawing the(ahv)2–hv graph,it can be seen that the band gap decreased after being annealed in the air, but increased in nitrogen gas.The PL spectra and x-ray irradiation spectra show that the luminescent intensity of the sample annealed in the air increased substantially,while decreased for the sample annealed in nitrogen.The PL decay time of the Ta:β-Ga2O3 annealed in the air increased significantly compared with that of the Ta:β-Ga2O3 sample without annealing, but the tendency after annealing in nitrogen gas was opposite.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.51972319,52002386,and 52072183)the Science and Technology Commission of Shanghai Municipality(No.19520744400)the Shanghai Science and Technology Commission(No.20511107400)。
文摘Sb-doped β-Ga_(2)O_(3) crystals were grown using the optical floating zone(OFZ) method.X-ray diffraction data and X-ray rocking curves were obtained,and the results revealed that the Sb-doped single crystals were of high quality.Raman spectra revealed that Sb substituted Ga mainly in the octahedral lattice.The carrier concentration of the Sb-doped single crystals increased from 9.55 × 10^(16) to 8.10 × 10^(18) cm^(-3),the electronic mobility depicted a decreasing trend from 153.1 to108.7 cm~2·V^(-1)·s^(-1),and the electrical resistivity varied from 0.603 to 0.017 Ω·cm with the increasing Sb doping concentration.The un-doped and Sb-doped β-Ga_(2)O_(3) crystals exhibited good light transmittance in the visible region;however,the evident decrease in the infrared region was caused by increase in the carrier concentration.The Sb-doped β-Ga_(2)O_(3) single crystals had high transmittance in the UV region as well,and the cutoff edge appeared at 258 nm.
基金supported by the Natural Science Foundation of Shanghai under Grant No.15ZR1444700
文摘A highly transparent Eu^(3+)-doped CaGdAlO_4(CGA) single crystal is grown by the floating zone method.The segregation coefficient,x ray diffraction,and x ray rocking curve are detected,and the results reveal that the single crystal is of high quality.The f –f transitions of Eu^(3+) in the host lattice are discussed.The ~5D_0–~7F_2 emission transition at 621 nm(red light) is dominant over the ~5D_0–~7F_1 emission transitions at 591 and 599 nm(orange light),agreeing well with the random crystal environment of Eu^(3+) ions in a CGA crystal.The decay time of Eu:~5D_0 is measured to be 1.02 ms.All the results show that the Eu:CGA crystal has good optical characterization and promises to be an excellent red-fluorescence material.
基金supported by the National Natural Science Foundation of China (No. 61078054)the Science and Technology Commission of Shanghai Municipality (No. 11DZ1140301)
文摘YAG-Ce,Nd,and Yb phosphors with a triple-doped system are prepared by conventional solid-state reaction method.The fluorescence emission and excitation spectra are measured and analyzed.The influences of Yb3+ doping concentration on the emission of Yb3+ and Nd3+ in YAG-Ce,Nd,and Yb are studied.The fluorescence decay spectra,lifetime,and energy transfer efficiency of Ce3+ in different host materials of YAG-Ce and Yb,and YAG-Ce,Nd,and Yb are also compared.Furthermore,the trends of fluorescence decay spectra and the lifetimes of Nd3+ and Yb 3+ in YAG-Ce,Nd,and Yb with the increase of Yb3+ concentration are discussed.Results indicate that YAG-Ce,Nd,and Yb are good candidates for downconverting phosphor,with energy transfer efficiency reaching as high as 82.8%.
基金supported by the National Natural Science Foundation of China (Nos.50472032and50672105)the Science and Technology Commission of Shanghai Municipality (No.08DZ1140900)
文摘V-doped MgAl6O10 is grown by the conventional Czochralski method. The crystal structure and the cell parameters are analyzed through X-ray diffraction experiments. The absorption and emission spectra are investigated. Under pumping at 324 nm, the emission spectra of V-doped MgAl6O10 obtain two emission peaks at the wavelengths of 471 and 570 nm. Two emission bands of the spectra combine to produce a spectrum that is perceived as white by the naked eye. Therefore, V-doped MgAl6O10 single crystal can be applied as substrate for phosphor-free ultraviolet (UV)-white light-emitting diodes (LEDs).
