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A DOUBLE-TEMPERATURE-GRADIENT TECHNIQUE FOR THE GROWTH OF PURE C60 SINGLE CRYSTALS FROM THE VAPOR PHASE 下载免费PDF全文
Pure C60 single crystals were grown by a sublimation-condensation method in an evacuated dosed quartz tube situated in a double-temperature-gradient furnace. Large C60 single crystals, up to a size of 0.6 mm×1.0 mm×2.0 mm with quite smooth and shiny faces, were obtained. X-ray diffraction, electron diffraction and X-ray morphology were carried out and showed that the quality of large C60 single crystals grown by the double-temperature-gradient technique is excellent. In this paper the experimental results of the growth of large C60 single crystals are reported and the morphological and structural characterizations are discussed in detail. 相似文献
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M. Haluška H. Kuzmany M. Vybornov P. Rogl P. Fejdi 《Applied Physics A: Materials Science & Processing》1993,56(3):161-167
Fullerite single crystals were prepared by a sublimation-condensation method in a closed evacuated glass tube situated in a double-temperature-gradient furnace. Crystals of various size and up to 9 mg weight with well expressed smooth and shiny faces were obtained. X-ray analysis, interfacial angle measurements and observed morphological habits of selected crystals of C60 confirm the theoretically predicted and experimentally well established fcc structure at room temperature with two types of morphological faces, namely {111} and {100}. A strong tendency to twinning was observed. In the case of C70 crystals, a pure fcc structure was observed. Information on growth kinetics and on instability versus exposure to air and light were obtained from surface studies. Characteristic changes in a thin surface layer were observed when crystals were exposed to air and light. A new phase of C60 stabilized by oxygen was characterized. 相似文献
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用气相法生长出了毫米尺寸的具有规则晶面和金属光泽的高质量的纯C60单晶.X射线衍射分析表明,C60单晶在室温下具有面心立方(fcc)结构,晶格常数为α=1.4199(4)nm。用扫描电子显微镜和光学显微镜观察了C60单晶的形貌,除观察到fcc结构的晶体所特有的{111}和{200}两种稳定晶面以及非常容易形成的孪晶之外,还发现了在{111}面上的树枝状、垄状和生长丘以及在{200}面上的树枝状、游泳池状和生长丘的生长缺陷。对C60
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B. Morosin X. -D. Xiang M. Fuhrer A. Zettl 《Applied Physics A: Materials Science & Processing》1993,57(2):171-174
Vapor grown crystals of C60 with thin flat triangular, rhombic or trapezoidal shapes of size to 1×2×0.001 mm as well as prismastic crystals typically 0.5×0.4×0.2 mm have been grown using a high temperature vapor transport method. Room temperature X-ray precession photography shows these crystals exhibit diffraction patterns consistent with those for either (a) single or (b) twinned crystals of the previously reported face-centered cubic structure or (c) a more complex cell of hexagonal symmetry with a=10.010(2) Å and c=49.064(11) Å. This latter from actually is a multiple twin containing both the face-centered cubic and the close-packed hexagonal structure types. The sharp diffraction maxima for either the single or the twinned crystals demonstrate that they consist of large coherent domains and are essentially free of planar defects parallel to the twin planes. 相似文献
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A. V. Bazhenov N. S. Sidorov S. S. Khasanov T. N. Fursova V. I. Orlov A. N. Izotov A. A. Levchenko I. V. Sleptsova 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(8):1031-1032
Fullerit C60 single crystals were grown by sublimation on Earth and under microgravity during the FOTON-M3 mission using the same growth
parameters and the same multizoned electrovacuum POLIZON-M furnace. IR spectroscopy and X-ray measurements revealed the considerably
better crystal structure of the crystals grown under microgravity. 相似文献
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V. V. Lemanov S. N. Popov V. V. Bakhurin N. V. Zaitseva 《Physics of the Solid State》2001,43(7):1336-1338
A new compound, diserine sulfate monohydrate, was synthesized, and single crystals of this compound were grown. X-ray diffraction studies were carried out, and the temperature dependences of the piezoelectric response of these crystals were measured. A conclusion was drawn that the crystals are orthorhombic with the space symmetry group C 1v -Pmm2 and that they apparently undergo phase transitions at 340 and 255 K. 相似文献
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A. M. Molodets V. V. Avdonin A. N. Zhukov V. V. Kim A. YU. Osip’yan N. S. Sidorov 《高压研究》2013,33(2):279-290
A study of electrophysical and thermodynamic properties of C60 single crystals under step shock loading has been carried out. The increase and the following reduction in specific electroconductivity of C60 fullerite single crystals at step shock compression up to pressure 30 GPa have been measured. The equations of state for face centred cubic (fcc) C60 fullerite as well as for two-dimensional polymer C60 and for three-dimensional polymer C60 (3D-C60) were constructed. The pressure–temperature states of C60 fullerite were calculated at step shock compression up to pressure 30 GPa and temperature 550 K. The X-ray diffraction studies of shock-recovered samples reveal a mixture of fcc C60 and a X-ray amorphous component of fullerite C60. The start of the formation of the X-ray amorphous component occurs at a pressure P m≈ 19.8 GPa and a temperature T m≈ 520 K. At pressures exceeding P m and temperatures exceeding T m, the shock compressed fullerite consist of a two-phase mixture of fcc C60 fullerite and an X-ray amorphous component presumably consisting of the nucleators of polymer 3D-C60 fullerite. The decrease in electroconductivity of fullerite can be explained by the percolation effect caused by the change of pressure, size and number of polymeric phase nuclei. 相似文献
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R. A. Dilanyan S. S. Khasanov S. I. Bredikhin A. F. Gurov V. V. Kveder Yu. A. Osip’yan A. I. Shalynin 《Journal of Experimental and Theoretical Physics》2001,93(6):1239-1244
The structure and phase transitions of C60 crystals doped with lithium by injecting metal ions from the superionic crystal-C60 single crystal heterojunction under electrodiffusion conditions are reported. The sample experienced irreversible transitions resulting in the virtually complete disappearance of EPR signals and MW conduction in the temperature range 320–370 K. In this temperature interval, a new C60 phase was formed; the phase contained polymeric chains of C60 molecules along the crystallographic c axis and lithium clusters. The structure of this phase was determined. Annealing at 620 K restored the EPR signal and, according to the X-ray data, the initial cubic structure of pure C60. The X-ray pattern, however, contained additional diffraction peaks, which was evidence of the presence of one more phase with a structure yet unknown. 相似文献
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G. Gensterblum L. -M. Yu J. -J. Pireaux P. A. Thiry R. Caudano J. -M. Themlin S. Bouzidi F. Coletti J. -M. Debever 《Applied Physics A: Materials Science & Processing》1993,56(3):175-183
C60 films have been grown in ultra high vacuum on various crystalline substrates and the structure of the films has been investigated by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The C60 films form randomly oriented nanocrystals on Si(100), mesoscopic polycrystals on GaSe(0001) and microscopic single crystals on GeS(001). The vibrational structure of the C60/substrate interfaces is analyzed in detail by HREELS carried out in the dipole and impact scattering regimes. It is shown that the epitaxy of C60 on GeS(001) is induced by the weak van der Waals bonding and the peculiar corrugation of the substrate surface. 相似文献
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A method for rapidly intercalating C60 fullerene crystals has been implemented using self-propagating high-temperature synthesis. The method has been used to intercalate
C60 fullerene crystals with alkali (K, Rb) and alkaline-earth (Ca, Ba) metals. The superconducting transition temperatures of
the prepared compounds have been measured. The C60 fullerene crystals intercalated with calcium have been investigated using X-ray diffraction. 相似文献
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《Surface science》1994,317(3):L1129-L1135
Epitaxial silicon carbide films are grown on Si(100) and Si(111) substrates at surface temperatures between 950 and 1250 K via c60 precursors. Films have been grown up to thicknesses greater than 1 μm. The growth rate of the SiC film is not limited by the surface reaction rate of C60 with silicon at these temperatures, rather by the arrival rate of the reactants Si (by diffusion) or C60. This results in rapid film growth. Films have been characterized by low energy electron diffraction, X-ray diffraction, and Auger depth profiling. X-ray diffraction suggests the growth of β-SiC in the temperature range investigated. Auger depth profiling shows the film is stoichiometric. Selective crystalline silicon carbide growth is achieved on patterned silicon-silicon oxide samples. 相似文献
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《Current Applied Physics》2010,10(5):1261-1266
Non-linear optical manganese mercury teterathiocyanate glycol monomethyl ether [MnHg(SCN)4(C3H8O2)] compound was synthesized and single crystals were grown from water-glycol monomethyl ether (1:1) mixed solvent by slow cooling method. Structure and crystallinity of the grown crystal were confirmed by both single crystal and powder X-ray diffraction analysis. Presence of functional groups and coordination of glycol monomethyl ether and thiocyanate in MMTG were confirmed by FT-IR analysis. Optical transmittance and second harmonic generation of the grown crystal were studied by UV–Vis spectrum and Kurtz powder technique. A dielectric study was performed on the MMTG single crystal to study the power dissipation of the material in the presence of alternating electric field. Mechanical behaviour was analysed using Vicker’s microhardness test. Optical surface damage measurement was carried out to confirm the suitability of MMTG crystal for NLO applications. 相似文献
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本文描述了甩升华法生长ZnSe单晶的生长情况和晶体品质。为了获得高纯高完整性单晶,由高纯Zn和Se反应合成了ZnSe,设计了特殊形状的成核室,保证了在一个晶核上单晶的生长;同时在生长过程中控制组分分压,减小了化学计量比的偏差。通过偏光显微镜的观察和He-Ne激光散射的形貌分析表明,在生长速率小于0.5(毫米/天)情况下,在块状单晶体中观察不到生长带纹的条纹,但观察到位错缺陷。在液氦温度的光致发光光谱中首次观察到强的自由激子光谱和激子激发态的光谱;观察到典型的反射光谱和精细的束缚激子谱线,没有观察到2.4eV以下的深能级发光谱带。这些结果表明单晶的纯度和完整性是良好的。 相似文献
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X. T. Liu X. Q. Wang X. J. Lin G. H. Sun G. H. Zhang D. Xu 《Applied Physics A: Materials Science & Processing》2012,107(4):949-957
A novel potentially useful second harmonic generation (SHG) organometallic nonlinear optical (NLO) crystal: cadmium mercury thiocyanate bis(N-methylformamide), CdHg(SCN)4(C2H5NO)2 (CMTN), has been prepared, and large high-optical-quality single crystals with dimensions up to 30 ×27×9 mm3 have been grown by the temperature-lowering method. Its structural, physicochemical and optical properties are characterized by elemental analyses, X-ray powder diffraction, Fourier transform infrared and Raman spectroscopy, thermal analysis, powder SHG measurements and UV/Vis/NIR transmission. The specific heat has been determined to be 515.5 J?mol?1?K?1 at 300 K. CMTN possesses good physicochemical stability up to 128.5°C, exhibits powder SHG efficiencies 0.8 times that of urea and its UV transparency cutoff is 358 nm. By the use of the DFT/B3LYP/6-31G(d) method, the microscopic second order NLO behavior of CMTN has been investigated by computing the first-order hyperpolarizability together with that of CdHg(SCN)4 (CMTC) and CdHg(SCN)4(C3H8O2) (CMTG) crystals. The results have been explained based on their crystal structures. 相似文献
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The pure l-alanine alaninium nitrate (LAAN) single crystals and LAAN crystals doped with lanthanum oxide (La2O3), sodium chloride (NaCl), urea (CH4N2O), glycine (C2H5NO2) and thiourea (CH4N2S) were grown by slow evaporation method. The X-ray diffraction analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDAX) analysis, UV–vis spectral analysis, dielectric studies and powder SHG measurement are studied systematically. The slight changes in the lattice parameters were observed for the doped crystals compared to pure LAAN crystal. The incorporation of doping into the crystal lattice was confirmed by energy dispersive X-ray analysis. There is no change in the transmission window due to doping and the percentage of transmission in doped samples was found to increase as compared to that of pure LAAN crystal. The dielectric constant of pure crystal was found to be less than that of doped crystals. The AC conductivity was found to increase after doping and with the increase in temperature. A green radiation of 532 nm was observed from the pure and doped LAAN crystals confirming the second harmonic generation (SHG) of the crystals. 相似文献