采用传统固相法制备了(Na0.5Bi0.5)1-xLaxBi2Nb2O9(NBN-x La^3+,x=0.00,0.04,0.08,0.16,0.24,0.32,0.40)陶瓷,分析了稀土离子La^3+掺杂对Na0.5Bi2.5Nb2O9陶瓷的相结构、微观结构和电学性能的影响。XRD和拉曼结果表明La^3+成功进入NBN晶...采用传统固相法制备了(Na0.5Bi0.5)1-xLaxBi2Nb2O9(NBN-x La^3+,x=0.00,0.04,0.08,0.16,0.24,0.32,0.40)陶瓷,分析了稀土离子La^3+掺杂对Na0.5Bi2.5Nb2O9陶瓷的相结构、微观结构和电学性能的影响。XRD和拉曼结果表明La^3+成功进入NBN晶格内部并减弱了结构的正交畸变。La^3+掺杂引起的结构变化和氧空位浓度的降低使得陶瓷样品更易于被极化,压电活性提升。当x=0.24时,陶瓷的电学性能达到最佳:Tc=647℃,εr=328,tanδ=1.09%,d33=22.8 p C/N,Qm=3259。NBN-0.24La^3+陶瓷压电常数d33在高温下表现出良好的温度稳定性,样品在500℃下退火2 h,压电常数d33仍能保持在20.3 p C/N,为初始值的89%。展开更多
Our calculations demonstrate that the concentration of neutral oxygen vacancies can affect the geometrical structrue,electronic structure, and optical properties of α-quartz. Moreover, the distribution of the neutral...Our calculations demonstrate that the concentration of neutral oxygen vacancies can affect the geometrical structrue,electronic structure, and optical properties of α-quartz. Moreover, the distribution of the neutral oxygen divacancy can also exert some influence on the properties of α-quartz. The dissimilarity and similarities are presented in the corresponding density of state（DOS） and absorption spectrum. In addition, when a higher defect concentration is involved in α-quartz,the influence of E1 center on the geometry of α-quartz becomes more significant. However, the introduction of an E1 center barely results in any improvement compared with the influence produced by the corresponding neutral defect.展开更多
The role of deposition rate in the structural, optical and electrical properties of SnOthin films deposited by electron beam evaporation method is investigated by varying the deposition powers viz. 50, 75, and 100 W.T...The role of deposition rate in the structural, optical and electrical properties of SnOthin films deposited by electron beam evaporation method is investigated by varying the deposition powers viz. 50, 75, and 100 W.The structural characterization of the films is done by X-ray diffraction(XRD) technique. The surface morphology of the films is studied by scanning electron microscopy(SEM). Rutherford back scattering(RBS) measurements revealed the thickness of the films ranging from 200 nm to 400 and also a change in the concentration of oxygen vacancies which is found to be the maximum in the film deposited at the lowest deposition rate. Optical absorption spectrum is recorded using the UV–V is spectroscopy and the films are found to be transparent in nature. A shift in the absorption edge is observed and is attributed to a different level of allowed energy states in conduction band minimum. The Hall effect and electrical measurements show a variation in the carrier concentrations, mobility and resistivity of the films. In order to explore a better compromise in electrical and optical properties for transparent electrode applications, skin depths calculations are also done to find the optimized values of carrier concentration and mobility.展开更多
基金National Natural Science Foundation of China(51762024,51562014,51862016 and 51602135)Natural Science Foundation of Jiangxi Province(20171BAB216012,20192BAB206008 and 20192BAB212002)Science Foundation of Jiangxi Provincial Education Department of China(GJJ180718 and GJJ180739)。
文摘采用传统固相法制备了(Na0.5Bi0.5)1-xLaxBi2Nb2O9(NBN-x La^3+,x=0.00,0.04,0.08,0.16,0.24,0.32,0.40)陶瓷,分析了稀土离子La^3+掺杂对Na0.5Bi2.5Nb2O9陶瓷的相结构、微观结构和电学性能的影响。XRD和拉曼结果表明La^3+成功进入NBN晶格内部并减弱了结构的正交畸变。La^3+掺杂引起的结构变化和氧空位浓度的降低使得陶瓷样品更易于被极化,压电活性提升。当x=0.24时,陶瓷的电学性能达到最佳:Tc=647℃,εr=328,tanδ=1.09%,d33=22.8 p C/N,Qm=3259。NBN-0.24La^3+陶瓷压电常数d33在高温下表现出良好的温度稳定性,样品在500℃下退火2 h,压电常数d33仍能保持在20.3 p C/N,为初始值的89%。
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11176020 and 11374217)the Doctoral Program of Higher Education of China(Grant No.20100181110080)
文摘Our calculations demonstrate that the concentration of neutral oxygen vacancies can affect the geometrical structrue,electronic structure, and optical properties of α-quartz. Moreover, the distribution of the neutral oxygen divacancy can also exert some influence on the properties of α-quartz. The dissimilarity and similarities are presented in the corresponding density of state（DOS） and absorption spectrum. In addition, when a higher defect concentration is involved in α-quartz,the influence of E1 center on the geometry of α-quartz becomes more significant. However, the introduction of an E1 center barely results in any improvement compared with the influence produced by the corresponding neutral defect.
文摘The role of deposition rate in the structural, optical and electrical properties of SnOthin films deposited by electron beam evaporation method is investigated by varying the deposition powers viz. 50, 75, and 100 W.The structural characterization of the films is done by X-ray diffraction(XRD) technique. The surface morphology of the films is studied by scanning electron microscopy(SEM). Rutherford back scattering(RBS) measurements revealed the thickness of the films ranging from 200 nm to 400 and also a change in the concentration of oxygen vacancies which is found to be the maximum in the film deposited at the lowest deposition rate. Optical absorption spectrum is recorded using the UV–V is spectroscopy and the films are found to be transparent in nature. A shift in the absorption edge is observed and is attributed to a different level of allowed energy states in conduction band minimum. The Hall effect and electrical measurements show a variation in the carrier concentrations, mobility and resistivity of the films. In order to explore a better compromise in electrical and optical properties for transparent electrode applications, skin depths calculations are also done to find the optimized values of carrier concentration and mobility.
