共查询到20条相似文献,搜索用时 265 毫秒
1.
2.
The epitaxial Mno0.98Cr0.02Te films on single crystal Al2O3 (0001) substrates were prepared by pulsed laser deposition. The X-ray diffraction and scanning electron microscopy results showed that the good continuous epitaxial film was obtained with substrate temperature of 500 ℃. When the substrate temperature reached 700 ℃, the film was island growth and the manganese oxides phase appeared. The temperature dependence of both the magnetization and electrical resistance showed a sharp rise at around 60 K due to the magnetoelastic coupling. The temperature dependence of the electrical resistance of Mno0.98Cr0.02Te provided evidence for a transition from the metallic to semiconducting state at 305 K due to the spin disorder scattering with a large contribution from the influence of magnon drag. 相似文献
3.
采用水热法合成Bi_2Te_3粉体,将炭黑(CB)与其掺杂制备不同比例的碲化铋/炭黑(Bi_2Te_3/CB)复合材料,研究复合材料的热电性能。同时采用TGA、SEM、XRD等分析方法表征Bi_2Te_3/CB复合材料的结构,探究微观结构与热电性能的关系。研究发现:室温下,CB的引入使Bi_2Te_3/CB复合材料的热导率大大降低(0.5957 W/(m·K)降到0.0888 W/(m·K));随着Bi_2Te_3含量的增加,复合材料的电导率、热导率均增大,Seebeck系数先增加后降低;当Bi_2Te_3含量为88.9%时,在558℃烧结10min所得的Bi_2Te_3/CB复合材料室温下热电优值ZT最大(ZT=0.21)。虽然ZT值未能达到应用价值,但是CB的添加为改善Bi_2Te_3材料的热电性能,尤其在降低材料的热导率方面,提供了新方法和新思路。 相似文献
4.
电化学制备Bi2Te3纳米线用于微型温差发电器 总被引:1,自引:0,他引:1
借助于电化学沉积的方法,在氧化铝纳米孔内生长Bi2Te3材料,从而形成温差电纳米线阵列.利用SEM,XRD and TEM分析手段对制备的纳米线形貌和结构进行了分析,测量了纳米线的组成和温差电性能.p型和n型Bi2Te3纳米线材料的Seebeck系数经过测量分别为260μV/K和-188μV/K(307K),比同类的块状温差电材料性能高.同时研究了沉积电位对氧化铝模板中纳米孔的填充率的影响,并对纳米线阵列的电阻进行了测量.尝试了利用n型和P型Bi2Te3纳米线阵列制备一种新型的微型温差发电器. 相似文献
5.
在GeTe-Bi2Te3赝二元系统中, (GeTe)n(Bi2Te3)m化合物往往具有较低的晶格热导率, 但其中很多组分的热电性能尚未得到系统研究。本研究通过熔融、淬火、退火结合放电等离子烧结工艺制备了一系列(GeTe)nBi2Te3(n=10, 11, 12, 13, 14)单相多晶样品, 并对其相组成和热电性能进行表征和研究。掺杂Bi2Te3可以显著增强点缺陷声子散射, 大幅度降低材料的晶格热导率, 在723 K时, (GeTe)13Bi2Te3样品的总热导率低至1.63 W?m -1?K -1。此外, 掺杂Bi2Te3和调控GeTe的相对含量, 提高了材料的载流子有效质量, 即使在较高的载流子浓度下, 样品依然保持较高的塞贝克系数和功率因子, 在723 K, (GeTe)13Bi2Te3样品获得最大的功率因子为2.88×10 -3 W?m -1?K -2, 最终(GeTe)13Bi2Te3样品在723 K获得的最大ZT值达到1.27, 较未掺杂的GeTe样品提高了16%。 相似文献
6.
7.
Shuai Dong Dandan Yu Jie Yang Li Jiang Jiawei Wang Liwei Cheng Yan Zhou Honglei Yue Hua Wang Lin Guo 《Advanced materials (Deerfield Beach, Fla.)》2020,32(23):1908027
Currently, exploring high-volumetric-capacity electrode materials that allow for reversible (de-)insertion of large-size K+ ions remains challenging. Tellurium (Te) is a promising alternative electrode for storage of K+ ions due to its high volumetric capacity, confirmed in lithium-/sodium-ion batteries, and the intrinsic good electronic conductivity. However, the charge storage capability and mechanism of Te in potassium-ion batteries (KIBs) have not been unveiled until now. Here, a novel K–Te battery is constructed, and the K+-ion storage mechanism of Te is revealed to be a two-electron conversion-type reaction of 2K + Te ↔ K2Te, resulting in a high theoretical volumetric capacity of 2619 mAh cm−3. Consequently, the rationally fabricated tellurium/porous carbon electrodes deliver an ultrahigh reversible volumetric capacity of 2493.13 mAh cm−3 at 0.5 C (based on Te), a high-rate capacity of 783.13 mAh cm−3 at 15 C, and superior long-term cycling stability for 1000 cycles at 5 C. This excellent electrochemical performance proves the feasibility of utilizing Te as a high-volumetric-capacity active material for storage of K+ ions and will advance the practical application of KIBs. 相似文献
8.
9.
10.
11.
YongqinCHANG WanqiJIE XipingGUO FuyiCHEN WeijunAN 《材料科学技术学报》2003,19(6):610-612
MnxCd1-xIn2Te4 (x=0.1) ingot was successfully grown by the modified Bridgman technique, which applied the accelerated crucible rotation technique (ACRT) in Bridgman process, or briefly ACRT-B. The growth interface profile shape and the composition distribution in the MnxCd1-xIn2Te4 (x=0.1) ingot were analyzed. Even though the stoichiometric composition was synthesized in the original ingot, the composition has been redistributed during the ACRT-B growth process. Mn and Cd contents decrease while In increases along the longitudinal axis. The partition ratios of solutes Mn, Cd and In at the growth interface are evaluated by a mathematical method based on the experimental data, which are found to be 1.286, 1.926 and 0.729 in α phase growth process, and 1.120, 1.055 and 0.985 in β phase growth process, respectively. In the radial direction,Mn and Cd contents increase while In decreases with the distance from the centerline of the ingot. 相似文献
12.
Cu2SnSe3基化合物作为一种绿色环保的新型热电材料, 近年受到了研究者的广泛关注。然而, 本征Cu2SnSe3基化合物载流子浓度低、电性能较差。为优化Cu2SnSe3化合物的电热输运性能, 本研究采用熔融、退火结合放电等离子烧结技术制备了一系列Cu2SnSe3-xTex (x=0~0.2)和Cu2Sn1-yInySe2.9Te0.1 (y=0.005~0.03)样品, 研究了Te固溶和In掺杂对材料电热输运性能的影响。Te在Cu2SnSe3-xTex (x=0~0.2)化合物中的固溶度为0.10, Te固溶显著增加了材料的载流子有效质量, 从本征Cu2SnSe3样品的0.2me增加到Cu2SnSe2.9Te0.1样品的0.45me, 显著提高了材料的功率因子, Cu2SnSe2.99Te0.01样品在300 K下获得最大功率因子为1.37 μW·cm-1·K-2。为了进一步提高材料的电传输性能, 本研究以Cu2SnSe2.9Te0.1为基体并选取In在Sn位掺杂。In掺杂将Cu2SnSe3基化合物的载流子浓度从5.96×1018 cm-3 (Cu2SnSe2.9Te0.1)显著提高到2.06×1020 cm-3 (Cu2Sn0.975In0.025Se2.9Te0.1)。调控载流子浓度促进了材料多价带参与电传输, 材料的电导率和载流子有效质量显著增加, 功率因子得到大幅度提升, 在473 K下Cu2Sn0.995In0.005Se2.9Te0.1化合物获得最大功率因子为5.69 μW·cm-1·K-2。由于电输运行性能显著提升和晶格热导率降低, Cu2Sn0.985In0.025Se2.9Te0.1样品在773 K下获得最大ZT为0.4, 较本征Cu2SnSe3样品提高了4倍。 相似文献
13.
利用温度梯度溶液生长法(TGSG)在较低生长温度下制备了掺Al和掺In的x=0.2的Cd1-xZnxTe晶体,晶体起始生长温度约为1223K,温度梯度为20~30K/cm,坩埚的下降速度为1mm/h。采用红外显微镜、傅里叶红外光谱仪、扫描电镜能谱仪(SEM/EDS)和I-V测试分别研究了晶体中的Te夹杂相、红外透过率、Zn组分分布和电阻率。结果显示CdZnTe晶锭初始生长区、稳定生长区的Te夹杂相密度分别为8.3×103、9.2×103/cm-2,比垂直布里奇曼法生长的晶体低约1个数量级,红外透过率分别为61%、60%。Al掺杂CdZnTe晶体的电阻率为1.05×106Ω.cm,而In掺杂CdZnTe晶体的电阻率为7.85×109Ω.cm。晶锭初始生长区和稳定生长区的Zn组分径向分布均匀。 相似文献
14.
IR images reveal that Te inclusions exist in CdZnTe crystal in the form of square, hexagonal and triangular shapes. The density of Te inclusions for sizes above 5 μm sharply varied from 2.27 × 103 cm−2 to 4.52 × 105 cm−2 with a consequent reduction in IR transmittance from ∼60.5% to ∼55% when the Te-rich volume increased to 83 ppma. Raman spectra suggested that the origin of a new peak at 262.5 cm−1 could be a secondary phonon with A1 symmetry and E symmetry of Te inclusions. The peaks of triangular Te inclusions in Te-rich CdZnTe wafers were shifted to high energy, suggesting that compressive stress existed around the Te inclusions. 相似文献
15.
16.
采用Bridgman法生长CdZnTe晶体.分别采用红外透过显微镜和正电子湮灭寿命谱仪研究了CdZnTe晶体中的Te夹杂相、Cd空位等缺陷与坩埚中的自由空间量大小的关系.结果表明:随着坩埚自由空间量的减小,晶体中Te夹杂相密度从6.67×104/cm2降低到2.36×103/cm2,且Te夹杂相尺寸减小;晶体的正电子平均寿命值随着坩埚自由空间量的减小从325.4 ps降低到323.4 ps,表明晶体的Cd空位浓度及微结构缺陷减少;晶体的红外透过率和电阻率则随着坩埚自由空间量的减小大幅提高,进一步表明坩埚中自由空间量的减小能够有效地降低晶体中的缺陷浓度. 相似文献
17.
按照配方熔炼制成Sb-Se系和Ge-Sb-Te系合金,对其组织结构进行了观察测试,研究结果表明,制备的合金组织比较均匀,X射线衍射结果表明,Sb-Se系合金1#样品有Sb析出,2#样品有Se析出,符合化学计量比的3#样品全部形成Sb2Se3共晶体。Ge-Sb-Te系合金5#样品有Sb析出,而符合化学计量比的4#样品形成GeSb2Te4共晶体。 相似文献
18.
Recent Progress in the Design of Advanced Cathode Materials and Battery Models for High‐Performance Lithium‐X (X = O2, S,Se, Te,I2, Br2) Batteries 下载免费PDF全文
Jiantie Xu Jianmin Ma Qinghua Fan Shaojun Guo Shixue Dou 《Advanced materials (Deerfield Beach, Fla.)》2017,29(28)
Recent advances and achievements in emerging Li‐X (X = O2, S, Se, Te, I2, Br2) batteries with promising cathode materials open up new opportunities for the development of high‐performance lithium‐ion battery alternatives. In this review, we focus on an overview of recent important progress in the design of advanced cathode materials and battery models for developing high‐performance Li‐X (X = O2, S, Se, Te, I2, Br2) batteries. We start with a brief introduction to explain why Li‐X batteries are important for future renewable energy devices. Then, we summarize the existing drawbacks, major progress and emerging challenges in the development of cathode materials for Li‐O2 (S) batteries. In terms of the emerging Li‐X (Se, Te, I2, Br2) batteries, we systematically summarize their advantages/disadvantages and recent progress. Specifically, we review the electrochemical performance of Li‐Se (Te) batteries using carbonate‐/ether‐based electrolytes, made with different electrode fabrication techniques, and of Li‐I2 (Br2) batteries with various cell designs (e.g., dual electrolyte, all‐organic electrolyte, with/without cathode‐flow mode, and fuel cell/solar cell integration). Finally, the perspective on and challenges for the development of cathode materials for the promising Li‐X (X = O2, S, Se, Te, I2, Br2) batteries is presented. 相似文献
19.
Naukenova Aigul Sagindykovna Bekaulova Aliya Amankulovna Mamitova Aigul Dzhanabaevna SadykovZhenis Abzhanovich Kerimbekova Zaurekul Maidanbekovna Tolegen Marzhankul Erhozhakyzy RamatullaevaLazzat Immamadinovna Tursynbekova Elmira Nurlankyzy 《材料科学与工程:中英文B版...》2013,(12):812-816
In article, the methodology of mathematical modeling of periodic reactors with agitating in the conditions of formation and sedimentation of insoluble solid phase in a working zone on the basis of diffusive model is suggested. Also equations for calculation of the general concentration and average order of clusters of insoluble phase in the periodic reactor are offered. The methodology of calculation of processes of insoluble solid phase aggregation in systems with chemical reactions of the first and pseudo-first orders is developed, namely: equation for calculation of evolution of total clusters' number and average order of globules in system are developed, by taking into account kinetic constants of chemical reaction and elements of aggregation matrix. 相似文献
20.
Padmakar G. Chavan Mahendra A. More Madhvi Sharma Umananda M. Bhatta Dilip S. Joag 《Vacuum》2009,83(11):1307-1310
Tellurium nanorods were grown on silicon (111) substrates by thermal evaporation. The synthesized Te nanorods were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), prior to the field emission investigations. The TEM image revealed that the nanorods are needle-like having diameter less than 20 nm and length in the range of 200-400 nm. The selected area electron diffraction (SAED) pattern and high resolution TEM micrographs clearly reveal the crystalline nature of the Te nanorods. The field emission studies were carried out in a planar diode (close proximity) configuration at background pressure of ∼1 × 10−9 mbar. An emission current density of ∼8.5 μA/cm2 has been drawn at an applied field of ∼3.2 V/μm. The Folwer-Nodhiem plot, showed a non-linear behaviour. The high value of field enhancement factor (β ∼ 1 × 104), estimated from the slope of the F-N plot, suggests that the emission is indeed from the nanometric tips of the Te nanorods. The emission current stability studied at the preset value ∼3.5 μA over duration of more than 3 h is found to be very good, suggesting the use of Te nanorods as promising electron source for field emission based micro/nano-electronic devices. 相似文献