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1.
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
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S. Wang Y. Zhou Y. Zhu Q. Zhang Z. Chen H. Lu S. Dai G. Yang 《Journal of Superconductivity and Novel Magnetism》2003,16(3):585-588
The crystal structure and superconductivity of MgB2 thin films grown on various oxide substrates were investigated by X-ray diffraction and resistance measurement. The films were prepared by a two-step method, in which precursors B films were annealed in Mg vapor at 900○C. The X-ray diffraction shows that the MgB2 films grown on C–AL2O3, R–AL2O3, and MgO (001) are c-axis oriented while the films grown on SrTiO3 (001), LaAlO3 (001), and ZrO2 (001) are aligned with the (101) direction normal to the substrate planes. All the grown films show superconductivity and their transition temperature varies with the substrates in the range of 34–39 K. We think that the transition temperature variation is probably due to the lattice matching between the film and the substrate, as well as the interdiffusion at the film/substrate interface. The experimental results suggest that if there is no severe interdiffusion at the film/substrate interface in the high temperature annealing process, more substrates could be used for the growth of MgB2 films using the two-step method. 相似文献
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硅基外延β-SiC薄膜在不同刻蚀气体中的等离子体刻蚀研究 总被引:2,自引:0,他引:2
用等离子体刻蚀(PE)工艺,以四氟化碳(CF4)和六氟化硫(SF6)以及它们与氧气(O2)的混合气体作为刻蚀气体分别对Si基外延生长的β-SiC单晶薄膜进行了刻蚀工艺研究。结果表明在同样刻蚀工艺条件下,以SF6+O2作为刻蚀气体要比以CF4+O2作为刻蚀气体具有更高的刻蚀速率;在任何气体混合比条件下经SF6+O2刻蚀后的样品表面都不会产生富碳(C)表面的残余SiC层;而经CF4+O2刻蚀后的样品表面是否产生富C表面残余SiC层则与气体混合比条件有关,但刻蚀后的样品表面更为细腻。文中还对不同刻蚀气体下的刻蚀产物进行了讨论比较。 相似文献
5.
The epitaxial Mn_(0.98)Cr_(0.02)Te films on single crystal Al_2O_3(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 reached700 ℃,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 Mn_(0.98)Cr_(0.02)Te 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
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用直流磁控溅射方法在Si(100)面及载玻片上制备了Sb掺杂TiO2薄膜.利用XRD光谱研究了Sb对其薄膜结晶情况的影响,用AFM观察其表面形貌,利用分光光度计测量了TiO2薄膜的光学特性及其对亚甲基蓝的分解活性,通过测量和计算表面对水的接触角来衡量光致亲水性.研究结果表明纯TiO2薄膜为锐钛矿型,适量Sb的掺杂能使TiO2薄膜的结晶有显著改善,并出现Ti2O3和金红石相TiO2,薄膜的光催化活性和光致亲水性明显改善.随着掺杂量的增加,TiO2薄膜的吸收边逐渐红移.但Sb掺杂过量时,破坏了二氧化钛原有的晶格结构,光催化活性和光致亲水性也相应降低. 相似文献
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使用脉冲激光沉积(PLD)方法在柔性衬底PMMA和PET上制备了具有高c轴择优取向的AZO(ZnO∶Al)薄膜。通过X射线衍射(XRD)、紫外可见分光光度计(UV-Vis)和纳米划痕仪,研究了在不同衬底下生长的薄膜样品的晶体结构、光学性能和附着力。结果表明,两种柔性衬底上生长的AZO薄膜都是单一的ZnO六方相,可见光范围内光学透过率均大于85%;PMMA、PET衬底上AZO薄膜的临界载荷数值分别为31.31mN和16.97mN,PET衬底上ITO薄膜的临界载荷数值为40.55mN。 相似文献
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溶胶—凝胶法制备TiO2—SiO2复合薄膜的研究 总被引:8,自引:0,他引:8
采用溶胶-凝胶方法在单晶Si基片上制备了TiO2-SiO2复合薄膜,研究了溶剂、pH值对先体溶液成胶时间的作用,溶液的浓度、甩胶时的旋转速度、涂覆层数以及热处理温度对薄膜厚度、光学性能的影响。薄膜的折射率随温度增大,其主要贡献来自于薄膜中结构的变化。并测量了薄膜的I-V、C-f特性,由于薄膜中的热击穿效应而使得TiO2含量较高的薄膜2的I-V呈非线性变化。 相似文献
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S. Wang Y. Zhou Y. Zhu Q. Zhang Z. Chen H. Lu S. Dai G. Yang 《Journal of Superconductivity》2003,16(3):585-588
The crystal structure and superconductivity of MgB2 thin films grown on various oxide substrates were investigated by X-ray diffraction and resistance measurement. The films were prepared by a two-step method, in which precursors B films were annealed in Mg vapor at 900C. The X-ray diffraction shows that the MgB2 films grown on C–AL2O3, R–AL2O3, and MgO (001) are c-axis oriented while the films grown on SrTiO3 (001), LaAlO3 (001), and ZrO2 (001) are aligned with the (101) direction normal to the substrate planes. All the grown films show superconductivity and their transition temperature varies with the substrates in the range of 34–39 K. We think that the transition temperature variation is probably due to the lattice matching between the film and the substrate, as well as the interdiffusion at the film/substrate interface. The experimental results suggest that if there is no severe interdiffusion at the film/substrate interface in the high temperature annealing process, more substrates could be used for the growth of MgB2 films using the two-step method. 相似文献
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以玻璃为载体,采用溶凝胶胶法制备Pb2 -TiO2薄膜.采用AFM、XRD等技术,考察Pb2 掺杂后对TiO 2晶型结构和光催化活性的影响,结果表明,在相同制备条件下掺杂后使TiO2晶型由锐钛型向金红石型转变温度降低,经AFM分析,掺杂后使TiO2粒径增大,苯酚水溶液的光催化氧化分解反应结果表明,掺杂后TiO2的光催化活性有所提高. 相似文献
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The bonding and electronic structure of Cu/(0001)Al2O3 and Cu/(1120)Al2O3 interfaces has been studied experimentally using spatially-resolved transmission electron energy loss spectroscopy.The specimen were prepared by depositing Cu on single-crystal α-Al2O3 substrates,which have been Ar^ -ion sputter-cleaned prior to the growth of Cu.For both orientations of theα-Al2O3 substrate,atomically abrupt interfaces formed as determined by high-resolution transmission electron microscopy.The investigations of the interfacial Cu-L2,3,Al-L2,3 and O-K energy loss near-edge structures,which are proportional to the site-and angular-momentum-projected unoccupied density of states above the Fermi level,indicate the existence of metallic Cu-Al bonds at the Cu/Al2O3 interface independent of the substrate orientation. 相似文献
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L. Valade D. de Caro J. -P. Savy I. Malfant C. Faulmann M. Almeida J. Fraxedas J. S. Brooks 《Journal of Low Temperature Physics》2006,142(3-4):397-400
Chemical vapor deposition (CVD) and electrodeposition (ED) were applied to grow thin films of molecule-based magnets and conductors.
Chemical vapor deposited films are illustrated by the M(TCNE)
x
(M = V, Cr, Nb, Mo) magnet series. V(TCNE)
x
and Cr(TCNE)
x
are room-temperature magnets. XANES/EXAFS studies on the air-stable Cr(TCNE)
x
have been performed to determine the chemical environment of the chromium within the polymeric network. Electrodeposition
on a silicon working electrode was applied to process thin films of numerous molecule-based conductors, namely, nonintegral
oxidation state compounds, charge transfer complexes, and single-component molecular conductors. Among the series of conductive
thin films, TTF[Ni(dmit2)]2 and Ni(tmdt)2 exhibit a metal-like behavior. 相似文献
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Van HU Chunwei YUAN 《材料科学技术学报》2006,22(2):239-244
Anatase TiO2 sol was synthesized under mild conditions (75℃ and ambient pressure) by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate (PMMA), SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope (FE-SEM) investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route. 相似文献
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T. Nurgaliev U. Topal B. Blagoev E. Mateev 《Journal of Superconductivity and Novel Magnetism》2012,25(7):2495-2498
Two La0.7Ca0.3MnO3(35?nm)/La0.7Sr0.3MnO3(30?nm) manganite bilayers were grown on LaAlO3(LAO) and Al2O3(ALO) substrates (i.e., the LCMO/LSMO/LAO and LCMO/LSMO/ALO samples) using a magnetron sputtering technique. The individual Curie temperatures of the LSMO and LCMO sublayers were 325?K, 225?K for the LCMO/LSMO/LAO sample and 325?K, 210?K for the LCMO/LSMO/ALO sample. The zero-field-cooled (ZFC) magnetization of the samples demonstrated maximums at ??150?K and ??170?K, respectively. The difference between the ZFC and field-cooled (FC) magnetizations was greater for the bilayer deposited on ALO substrate due to its polycrystalline nature. The coercive field of the LCMO/LSMO/LAO sample was greater at room temperature 298?K than at 150?K: This was interpreted as due to a change of the magnetic state of the LCMO sublayer in this temperature interval. 相似文献
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Hyung‐Jun Kim Hojoong Kim Suk Yang Jang‐Yeon Kwon 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(46)
Transition metal dichalcogenides (TMDCs) have recently been studied using various synthesis methods, such as chemical vapor deposition for large‐scale production. Despite the realization of large‐scale production with high material quality, a range of approaches have been made to solve the patterning issue of TMDCs focusing on the application of integrated devices; however, patterning is still under study to accurately represent nanoscale‐sized patterns, as well as the desired positions and shapes. Here, an insulating substrate is treated selectively with O2 plasma, and MoS2 growth is induced in the superhydrophilic area. Selectively well‐grown MoS2 patterns are confirmed by atomic force microscopy and Raman and photoluminescence spectroscopy. In addition, the grain size, according to the growth size, and grain boundary are analyzed by annual dark field transmission electron microscopy (TEM) and spherical aberration‐corrected scanning TEM to confirm the selective growth. An analysis of the device performance and the optical properties reveals an enhancement with increasing grain size. This method presents the path of the growth technique for patterning, as well as the direction that can be applied to devices and integrated circuits. 相似文献
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溶胶-凝胶法制备TiO2纳米薄膜的晶粒长大机理研究 总被引:5,自引:0,他引:5
通过sol-gel法在普通钠钙玻璃表面制备了均匀透明的锐钛矿型TiO2纳米薄膜.用透射电镜(TEM)、X射线衍射(XRD)和紫外可见吸收光谱(UV-VIS)等对薄膜的晶粒大小和透光率进行了表征.结果表明:随着镀膜次数和热处理时间的增加,薄膜中的平均晶粒大小接近线性增加.仅增加TiO2薄膜的热处理时间,薄膜中晶粒长大不明显,其吸收阀值未发生明显的红移.因此, 薄膜中晶粒长大的机理可能是: 上一次镀的TiO2晶粒成了下一次镀TiO2溶胶的晶核, 并在此基础上逐渐长大. 相似文献
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ZnO thin films were grown on Si (100) substrates by pulsed laser deposition using a ZnO target.The substrate temperature was varied in the range of room temperature to 800 ℃,and the oxygen partial pressure of 0.1333 Pa (1 m Torr) to 1333 Pa (10 Torr).The properties of the resulting films were investigated by photoluminescence (PL),grazing incidence X-ray diffraction (GIXRD),X-ray photoelectron spectroscopy (XPS),and field emission scanning electron microscopy (FESEM).Based on the ultraviolet (UV,~380 nm) to... 相似文献