Three-dimensional-ordered Yb/Er co-doped Bi2Ti207 inverse opal, powder, and disordered reference sam- ples are prepared and their upconversion （UC） emission properties and mechanisms are investigated. Sig- nificant ...Three-dimensional-ordered Yb/Er co-doped Bi2Ti207 inverse opal, powder, and disordered reference sam- ples are prepared and their upconversion （UC） emission properties and mechanisms are investigated. Sig- nificant suppression of UC emission is detected when the photonic band-gaps overlap with Er3＋ UC green emission bands. Interestingly, green and red UC emissions follow a two-photon process in the powder sample but a three-photon one in the inverse opal.展开更多
The Bi 2Ti 2O 7 thin films have been prepared on silicon by metalorganic deco mposition (MOD) technique using bismuth nitrate and titanium butoxide as source materials.The growth procedure of the Bi 2Ti 2O 7 thin film...The Bi 2Ti 2O 7 thin films have been prepared on silicon by metalorganic deco mposition (MOD) technique using bismuth nitrate and titanium butoxide as source materials.The growth procedure of the Bi 2Ti 2O 7 thin films was discussed.Th e surface morphology of the Bi 2Ti 2O 7 film was studied by the Electri c Force Microscope (EFM).The crystallization of the films was studied by X r ay diffraction (XRD).The Bi 2Ti 2O 7 thin film prepared on (100) silicon subs trate was proved with strong (111) orientation.The dielectric properties and the current voltage (I V) characteristics were measured.The dielectric constant o f the Bi 2Ti 2O 7 thin films vs.temperature and frequency in the interval 100 8 00℃ were studied.The dielectric constang is 118 and dielectric loss is 0.07 res pectively at 100KHz at room temperature.The resistivity of the Bi 2Ti 2O 7 th in film is higher than 1×10 12 (Ω·cm) under the applied voltage from -5V to 5V.For films 0.4μm thick annealed at 580℃ for 40 minutes,their leakage cu r r ent density is 4.06×10 -7 A/cm 2 at an applied voltage of 15V.This shows the films have very good insulating property. We observed the obviously ferroelectric phase transition and its Curie temperatu re in the Bi 2Ti 2O 7 ceramic.Capacitance vs.temperature was measured with 27 800℃ at 1kHz,10kHz,100kHz and 1MHz,respectively.展开更多
基金supported by the Natural Science Foundation of Yunnan Province(No.2010ZC038)the Open Foundation of Key Laboratory of Advanced Materialsin Rare,Precious and Non-ferrous Metals,Ministry of Education,and the Open Foundation of Key Laboratory of Advanced Materials of Yunnan Province(No.ZDS2010011B)
文摘Three-dimensional-ordered Yb/Er co-doped Bi2Ti207 inverse opal, powder, and disordered reference sam- ples are prepared and their upconversion （UC） emission properties and mechanisms are investigated. Sig- nificant suppression of UC emission is detected when the photonic band-gaps overlap with Er3＋ UC green emission bands. Interestingly, green and red UC emissions follow a two-photon process in the powder sample but a three-photon one in the inverse opal.
基金National Natural Science Foundation of China(51762024,51562014,51862016 and 51602135)Natural Science Foundation of Jiangxi province(20171BAB216012)Science Foundation of Jiangxi Provincial Education Department of China(GJJ170789,GJJ170804,GJJ180718 and GJJ170794).
文摘The Bi 2Ti 2O 7 thin films have been prepared on silicon by metalorganic deco mposition (MOD) technique using bismuth nitrate and titanium butoxide as source materials.The growth procedure of the Bi 2Ti 2O 7 thin films was discussed.Th e surface morphology of the Bi 2Ti 2O 7 film was studied by the Electri c Force Microscope (EFM).The crystallization of the films was studied by X r ay diffraction (XRD).The Bi 2Ti 2O 7 thin film prepared on (100) silicon subs trate was proved with strong (111) orientation.The dielectric properties and the current voltage (I V) characteristics were measured.The dielectric constant o f the Bi 2Ti 2O 7 thin films vs.temperature and frequency in the interval 100 8 00℃ were studied.The dielectric constang is 118 and dielectric loss is 0.07 res pectively at 100KHz at room temperature.The resistivity of the Bi 2Ti 2O 7 th in film is higher than 1×10 12 (Ω·cm) under the applied voltage from -5V to 5V.For films 0.4μm thick annealed at 580℃ for 40 minutes,their leakage cu r r ent density is 4.06×10 -7 A/cm 2 at an applied voltage of 15V.This shows the films have very good insulating property. We observed the obviously ferroelectric phase transition and its Curie temperatu re in the Bi 2Ti 2O 7 ceramic.Capacitance vs.temperature was measured with 27 800℃ at 1kHz,10kHz,100kHz and 1MHz,respectively.
