In Situ Fabrication of Metal–Organic Framework Thin Films with Enhanced Pervaporation Performance

The intrinsic porosity in the periodic structures of metal–organic frameworks (MOFs) endows them with a great potential for membrane separation. However, facile fabrication of crystalline MOF membranes has been challenging and limited to few materials for economic and environmental considerations. Herein, a continuous Zr-MOF thin film with a thickness of ≈180 nm has been fabricated via in situ recrystallization of MOF nanoparticles on the porous support under formic acid vapor. Owing to the inherent microporosity and the well-established hydrophilicity during membrane fabrication, the MOF thin films exhibit excellent pervaporation performance with separation factors of 2630, 501 and fluxes of 1.45, 1.41 kg m⁻² h⁻¹) for n-butanol dehydration and methanol/methyl tert-butyl ether (MeOH/MTBE) separation, respectively. The structural stability of the film has been further confirmed by its steady performance in the 10-day pervaporation test. This in situ recrystallization method induced by a trace amount of acid vapor with no extra ingredients opens a new avenue for the facile membrane fabrication of various MOF materials to feasibly realize their versatile potential as membrane materials.     

Epitaxial Growth of Bi-2201 and 2212 Thin Films by Magnetron Sputering

ＥｐｉｔａｘｉａｌＧｒｏｗｔｈｏｆＢｉ２２０１ａｎｄ２２１２ＴｈｉｎＦｉｌｍｓｂｙＭａｇｎｅｔｒｏｎＳｐｕｔｅｒｉｎｇＹ．Ｚ．ＺｈａｎｇＤ．Ｇ．ＹａｎｇＬ．ＬｉＢ．Ｒ．ＺｈａｏＨ．ＣｈｅｎＣ．ＤｏｎｇＨ．Ｊ．ＴａｏＨ．Ｔ．ＹａｎｇＪ．Ｗ．ＬｉＢ．Ｙ...     

Influence of Deposition Parameters on Surface Evolution of Sputtered Tantalum Thin Films

Tantalum thin films with different thicknesses varying from 50 nm to 600 nm were deposited on Si substrates by radio frequency magnetron sputtering as functions of deposition temperature（Ts） and bias voltage （Ub）. Surface roughness and its dynamic evolution behavior were quantitatively investigated by using atomic force microscopy（AFM）. With increasing Ts from 300 K to 600 K, surface roughness Rrms and dynamic exponent β decreases gradually. With the increase of Ub from 0 V to -150 V, Rrms and β first decrease and then increase. The dependence of Ts and Ub on the film surface evolution has been discussed in terms of surface diffusion, mound growth, and ion impinging effect.     

Influence of Magnet Configuration of on-axis Magnetron Sputering on The Quality of YBCO Thin Films

ＩｎｆｌｕｅｎｃｅｏｆＭａｇｎｅｔＣｏｎｆｉｇｕｒａｔｉｏｎｏｆｏｎａｘｉｓＭａｇｎｅｔｒｏｎＳｐｕｔｅｒｉｎｇｏｎＴｈｅＱｕａｌｉｔｙｏｆＹＢＣＯＴｈｉｎＦｉｌｍｓＹ．Ｚ．ＺｈａｎｇＬ．ＬｉＺ．Ｘ．Ｚｈａｏ（ＮａｔｉｏｎａｌＬａｂｏｒａｔｏｒｙｆ...     

Effects of Annealing Temperature on Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

ZnO thin films are deposited on n-Si（111） substrates by pulsed laser deposition（PLD） system. Then the samples are annealed at different temperatures in air ambient and their properties are investigated particularly as a function of annealing temperature. The microstructure, morphology and optical properties of the as-grown ZnO films are studied by X-ray diffraetion（XRD）. atomic force mieroseope（AFM）, Fourier transform infrared spectroscopy（FTIR） and photoluminescence（PL） spectra. The results show that the as- grown ZnO films have a hexagonal wurtzite structure with a preferred c-axis orientation. Moreover, the diameters of the ZnO crystallites become larger and the crystal quality of the ZnO fihns is improved with the increase of annealing temperature.     

Optical and Electrical Properties of Polyimide Thin Films Doped-Cu-phthalocyanine Polymerized by Vapor Phase Deposition

Using Cu-phthalocyanine(CuPc),4,4’-diaminodiphenyl ether and pyromellitic dianhydride as monomer materials, polyimide(PI) thin films doped-CuPc have been prepared onto glass substrate by vapor phase co-deposition polymerization under a vacuum of 2×10~(-3)Pa and thermal curing of polyamic acid film in at temperature of 150-200℃ for 60min. In this process, the polymerization can be carried out through controlling the stoichiometric ratio, heating time and deposition rates of the three monomers. IR spectrum identifies the designed chemical structure of the polymer. The absorption of polyimide doped-CuPc is very intense in vis-range and near-infrared by UV-Vis spectrum. And, the PI films doped-CuPc polymerized by vapor phase deposition have uniformity, fine thermal stability and good nonlinear optical properties, and the third-order optical nonlinear susceptibility χ~((3)) with degenerate four-wave mixing can be 1.984×10~(-9)ESU.     

Characterization and Stability of Na-doped p-type ZnO Thin Films Preparation by Reactive DC Magnetron Sputtering

Na-doped p-type ZnO thin films have been realized by DC reactive magnetron sputtering with a set of metal-Zn targets doped with various Na contents and under different substrate temperatures, respectively. Hall effect measurement, field-emission SEM, X-ray diffraction and optical transmission were carried out to investigate the effects of Na content and substrate temperature on the properties of p-type films. Results indicate that all the Na-doped ZnO films are strongly (002) oriented, and have an average t...     

In Situ Preparation and Thermoelectric Properties of B4C1−x –TiB2 Composites

B₄C_1?x –TiB₂ composites were prepared by in situ reactive spark plasma sintering of B₄C with addition of nano-TiO₂ powder. The effect of TiO₂ addition on the sinterability of boron carbide was studied. The composition and the microstructure of the dense composites are characterized by means of x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDX). The studies show that the composites contain boron carbide and TiB₂ phases with a homogeneous structure. In addition, the correlation between the composition and the thermoelectric properties was investigated. The electrical conductivity of the composite increased with increasing addition of TiO₂, and the Seebeck coefficient decreased with TiO₂ addition. The percolation threshold ø _c for TiB₂ in the B₄C_1?x –TiB₂ system was found to be in the range of 0.139 to 0.189. The thermal conductivity was reduced in the whole measuring temperature range from 50°C to 800°C below ø _c. Accordingly, a significant enhancement in the dimensionless figure of merit ZT of the composites was achieved compared with that of boron carbide without TiO₂ addition, with ZT achieving its maximum value at 10 wt.% TiO₂.     

Power Factor Characterization of Ge/SiGe Thermoelectric Superlattices at 300 K

To accurately characterize the efficiency of thermoelectric materials and characterize the maximum power that they can produce, a device using micro/nanofabrication techniques has been developed, enabling all three properties included in the figure of merit, ZT, of a thermoelectric material to be measured using a single device. The fabrication and testing of the device are presented. The electrical conductivity and Seebeck coefficient of Ge/SiGe heterostructures grown by low-energy plasma-enhanced chemical vapor deposition are used for demonstration. Experimental results as a function of quantum well width are presented, demonstrating power factors up to 6.02 ± 0.05 mW m^?1 K^?2 at 300 K. Modeling and physical characterization demonstrate that these results are presently limited by high threading dislocation density.     

Electrodeposition and Characterization of ZnO Thin Films

Thin films of ZnO were electrodeposited from an aqueous solution of Zn（NO3 ）2 on indium tin oxide（ITO）-covered glass substrate. The analysis of X-ray diffraction（XRD） and scanning electron micrograph （SEM） indicated that the obtained ZnO films had a compact hexagonal wurtzite type structure with preferable （002） growth direction. A sharp near-UV emission peak located at 380 nm and a strong orange-red emission peak located at 593 nm were observed in the photoluminescence, when excited with 325 nm wavelength at room temperature. Then the prepared ZnO films were introduced as anode phosphors into the field emission test. It was found that orange-red cathode-luminescence was observed and the luminescent brightness was enhanced by annealing. When annealing temperature increased about 600 ℃, the photoluminescence with peak of 531 nm and the green cathode-luminescence were observed. The tests showed that the brightness of about 2 × 102 cd/m^2 was obtained at electric field of 2 V/μm for annealed sample. The results revealed that the film could be a good kind of low-voltage drived cathode-luminescence phosphor.     

Microstructural Study of Zinc Sulfide Thin Films

ＭｉｃｒｏｓｔｒｕｃｔｕｒａｌＳｔｕｄｙｏｆＺｉｎｃＳｕｌｆｉｄｅＴｈｉｎＦｉｌｍｓ①②ＣＨＥＮＭｏｕｚｈｉ，ＬＩＵＺｈａｏｈｏｎｇ，ＷＡＮＧＹｕｊｉａｎｇＷＡＮＧＨｕｉ，ＤＥＮＧＣｈｏｎｇｈｕｉ（ＸｉａｍｅｎＵｎｉｖｅｒｓｉｔｙ，Ｘｉａｍｅｎ３６１...     

Electrochemical Deposition and Characterization of Thermoelectric Ternary (Bi x Sb1?x )2Te3 and Bi2(Te1?y Se y )3 Thin Films

Thermoelectric thin films of the ternary compounds (Bi _x Sb_1?x )₂Te₃ and Bi₂(Te_1?y Se _y )₃ were synthesized using potentiostatic electrochemical deposition on gold-coated silicon substrates from aqueous acidic solutions at room temperature. The surface morphology, elemental composition, and crystal structure of the deposited films were studied and correlated with preparation conditions. The thermoelectric properties of (Bi _x Sb_1?x )₂Te₃ and Bi₂(Te_1?y Se _y )₃ films, i.e., Seebeck coefficient and electrical resistivity, were measured after transferring the films to a nonconductive epoxy support. (Bi _x Sb_1?x )₂Te₃ thin films showed p-type semiconductivity, and the highest power factor was obtained for film deposited at a relatively large negative potential with composition close to Bi_0.5Sb_1.5Te₃. In addition, Bi₂(Te_1?y Se _y )₃ thin films showed n-type semiconductivity, and the highest power factor was obtained for film deposited at a relatively small negative potential, having composition close to Bi₂Te_2.7Se_0.3. In contrast to Bi₂Te_2.7Se_0.3 thin films, an annealing treatment was required for Bi_0.5Sb_1.5Te₃ thin films to achieve the same magnitude of power factor as Bi₂Te_2.7Se_0.3. Therefore, Bi₂Te_2.7Se_0.3 thin films appear to be good candidates for multilayer preparation using electrochemical deposition, but the morphology of the films must be further improved.     

Influence of the Design Features of a Magnetron Sputtering Deposition System on the Electrical and Optical Properties of Indium—Tin Oxide Films

Semiconductors - The influence of the relative position of a magnetron and substrate on the electrical and optical properties of a forming indium–tin oxide (ITO) layer is shown. The reasons...     

Structural and Dielectric Study of Thin Amorphous Layers of the Ge–Sb–Te System Prepared by RF Magnetron Sputtering

Semiconductors - The results of studying the structure and processes of dielectric relaxation in thin layers of Ge–Sb–Te are presented. The found permittivity dispersion and occurrence...     

Thermoelectric and Galvanomagnetic Properties of Layered n-Bi2 –xSbxTe3 –ySey Films

Semiconductors - The thermoelectric properties in the temperature range 4.2–300 K and magnetoresistance oscillations in strong magnetic fields at low temperatures are studied in...     

Electron Momentum Spectroscopy of Metal and Metal Oxide Thin Films

ＥｌｅｃｔｒｏｎＭｏｍｅｎｔｕｍＳｐｅｃｔｒｏｓｃｏｐｙｏｆＭｅｔａｌａｎｄＭｅｔａｌＯｘｉｄｅＴｈｉｎＦｉｌｍｓＸ．ＧｕｏＭ．ＶｏｓＳ．ＣａｎｎｅｙＡ．Ｓ．ＫｈｅｉｆｅｔｓＩ．Ｅ．ＭｃＣａｒｔｈｙＥ．Ｗｅｉｇｏｌｄ（ＥｌｅｃｔｒｏｎｉｃＳｔｒｕｃ...     

Structure and Magneto-Optical Characteristic Study of Optical Multilayer Thin Films

Based on the design theory of soft X-ray optical multilayer thin films and magneto-optic multilayer thin films, the metal multilayer thin films for the reflection of soft X-ray and ultraviolet ray, as well as the magneto-optic multilayer thin films for the magneto-optical memories were constructed. The metal multilayer thin films and the magneto-optic multilayer thin films were deposited with magnetron.sputtering. The detail of optical reflection characteristics, layered-structure, and surface and interface characteristics were studied. At the same time,the static magneto-optical characteristics and dynamic magneto-optical characteristics of the magneto-optical disk were investigated.     

TiO2 Thin Film UV Detectors Deposited by DC Reactive Magnetron Sputtering

CrystallineTiO2 thin films were prepared by DC reactive magnetron sputtering on indium--tin oxide(ITO) thin film deposited on quartz substrate, the photoconductive UV detector on TiO2 thin films was based on a sandwich structure of C/TiOz/ITO. The measurement of the I—V characteristics for these devices shows good ohmic contact. The photoresponse of TiO2 thin films was analyzed at different bias voltage. The detector shows a good photoresponse with a rise time of 2 s and a fall time of 40 s, the photocurrent is linearly increased with the bias voltage.