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Temperature and pressure induced Raman studies of C 60 oxide
摘要： We present temperature, laser power, and pressure dependent Raman spectral analysis of C60 oxide (C60O) thin films prepared by the photolysis method. The first order temperature, laser power, and pressure coefficients of the Raman frequencies are evaluated and are utilized for evaluating the thermal conductivity of C60O. Its thermal conductivity is found to be 0.7 W m-1 K-1 which is marginally higher than that of bulk C60. Raman frequencies corresponding to C–O and C–C bonds blue-shift with a decrease in temperature which is attributed to the thermal contraction of C60O molecules. The density functional measurements have been performed to optimize C60O structure. The contraction in the C–O bond length has been corroborated with the experimental Raman shifts at different temperatures and is used to evaluate the linear expansion coefficient of C60O. Pressure induced compression and polymerization of C60O clusters are also illustrated. This study highlights the interplay between thermal and mechanical transformations in the C60O cluster which may regulate its thermoelectric properties by tuning the intermolecular interactions.
关键词： pressure dependence,thermoelectric properties,Raman spectroscopy,thermal conductivity,C60 oxide,laser power dependence,temperature dependence
更新于2025-09-09 09:28:46
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-derived materials
摘要： Symmetry and dimensionality are essential factors defining lattice dynamics and conductivity (κ). Here, we critically examine these via ab initio Boltzmann transport applied to single chain and bulk electride Ba3N and Ba3NX (X = Sb,Bi). Chiral phonons in one-dimensional chains obey new symmetry-based scattering rules that limit thermal resistance. Weak chain coupling breaks these in the bulk, giving lower κ and large κ anisotropy. Curiously, intercalation of large X atoms binds chains more strongly, reducing the volume, yet gives lower κ and transforms the electronic behavior. Insights developed here can be more generally applied to other materials and provide avenues for predictive materials design.
关键词： symmetry,lattice dynamics,Ba3NX,dimensionality,thermal conductivity,Ba3N,chiral phonons,electride
更新于2025-09-09 09:28:46
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Facile Preparation of Silver Nanoparticles Decorated Boron Nitride Nanotube Hybrids
摘要： Blending polymer with thermally conductivity Metal nanoparticles-fillers, which can reducing ITR at a high fillers contents, have recently attracted intense attention. The interfacial thermal resistance (ITR) between fillers at a high filler doping contents causes a limited improvement of thermal conductivity. Fortunately, silver nanoparticles decorated fillers have potential to improve thermally conductivity by reducing ITR between fillers at a high filler content. However, how to fabricate pony-size silver nanoparticles decorated fillers hybrids simply is still a challenge. Herein, we report a facile synthesis of decorating boron nitride nanotube (BNNT) hybrids with AgNP (10-20 nm) by replacing between the Ag+ and -OH on the defect sites of BNNT. This strategy is a viable way to prepare metal nanoparticles-fillers which can be used in highly thermal conductivity.
关键词： boron nitride nanotube,thermal conductivity,hybrids,silver nanoparticles,interfacial thermal resistance
更新于2025-09-09 09:28:46
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Room Temperature Bonding of Wafers Using Si and Ge Films with Extremely Low Electrical Conductivity
摘要： The technical potential of room temperature bonding of wafers in vacuum using amorphous Si (a-Si) and Ge (a-Ge) films was studied. Transmission electron microscopy images revealed no interface corresponding to the original films surfaces for bonded a–Ge–a–Ge films. Analyses of film structure and the surface free energy at the bonded interface revealed higher bonding potential at the connected a–Ge–a–Ge interface than that of a–Si films. The electrical resistivity of a-Ge films is 0.62 ?m, which is lower than that of a-Si film (4.7 ?m), but 7–8 order higher than that of representative material films used for bonding in vacuum. Our results indicate that room temperature bonding using a–Ge films is useful to bond wafers without any marked influence on the electrical properties of devices on wafer surfaces caused by the electrical conductivity of films used for bonding.
关键词： room temperature bonding,electrical conductivity,amorphous Ge,wafer bonding,amorphous Si
更新于2025-09-09 09:28:46
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A Review of Manufacturing Materials and Production Methods for Frequency-Selective Structures [Wireless Corner]
摘要： This article presents a review of frequency-selective structure (FSS) manufacturing materials and production methods ranging from the common printed circuit board (PCB)-based designs to textile, ink, metal, or fluid prototypes. Our work gathers some of the most relevant solutions published by the scientific community and considers several examples depicted for each case. Additionally, the main physical parameters that may have a significant impact on FSS performance have been identified, e.g., electrical conductivity of the FSS conductive element and the relative permittivity and thickness of the FSS dielectric material. Finally, a comparative analysis of the materials and techniques is presented, which highlights the benefits and limitations of each solution.
关键词： printed circuit board,relative permittivity,metal,Frequency-selective structures,fluid prototypes,textile,ink,electrical conductivity,production methods,manufacturing materials
更新于2025-09-09 09:28:46
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Conductivity of Iron-doped Strontium Titanate in the Quenched and Degraded States
摘要： The electrical behavior of iron-doped strontium titanate (Fe:SrTiO3) single crystals equilibrated at 900 °C and quenched below 400 °C at various oxygen partial pressures ( ) was investigated via impedance spectroscopy and compared to defect chemistry models. Fe:SrTiO3 annealed and quenched between and Pa exhibits a conduction activation energy (EA) around 0.6 eV, consistent with ionic conduction of oxygen vacancies. However, sudden changes in EA are found to either side of this range; a transition from 0.6 to 1 eV is found in more oxidizing conditions, while a sudden transition to 1.1 and then 0.23 eV is found in reducing .These transitions, not described by the widely used canonical model, are consistent with predictions of transitions from ionic to electronic conductivity, based on first principles point defect chemistry simulations. These models demonstrate that activation energies in mixed conductors may not correlate to specific conduction mechanisms, but are determined by the cumulative response of all operative conduction processes and are very sensitive to impurities. A comparison to electrically degraded Fe:SrTiO3 provides insight into the origins of the conductivity activation energies observed in those samples.
关键词： defect chemistry,Strontium titanate,conductivity,resistance degradation
更新于2025-09-09 09:28:46
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Influence of Al/Si atomic ratio on optical and electrical properties of magnetron sputtered Al1-xSixOy coatings
摘要： This work presents a study on the influence of the Al/Si atomic ratio in dc magnetron sputtered Al1-xSixOy amorphous and transparent films upon their chemical composition, films’ structure, optical and electrical properties. Increasing silicon in Al1-xSixOy films, from 0 at. % up to 31.1 at. %, caused an increment of deposition rate and an increment in Al-O-Si energy bonds as confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis. On other hand, the optical constants (refractive index (n) and extinction coefficient (k)), dielectric constant, loss tangent (tan δ) and ac conductivity (σac) decrease when the amount of silicon in films increased. The results show that the refractive index shows small variations from linearity with vol% of Al2O3 (or SiO2). Dielectric constant and dielectric loss evidenced two dipolar contributions, attributed to defects located one at or near the substrate/oxide interface, and the other in the bulk of the oxide.
关键词： Electrical conductivity,Sputtering,Dielectric properties,Aluminum silicon oxide,Optical properties
更新于2025-09-09 09:28:46
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Lattice Thermal Conductivity Calculation of Sb2Te3 using Molecular Dynamics Simulations
摘要： We study lattice thermal conductivity of Sb2Te3 using molecular dynamics simulations. The interatomic potentials are fitted to reproduce total energy and elastic constants, and phonon properties calculated using the potentials are in reasonable agreement with first-principles calculations and experimental data. Our calculated lattice thermal conductivities of Sb2Te3 decrease with temperature from 150 K to 500 K. The in-plane lattice thermal conductivity of Sb2Te3 is higher than cross-plane lattice thermal conductivity of Sb2Te3, as in the case of Bi2Te3, which is consistent with the anisotropy of the elastic constants.
关键词： Thermal conductivity,Interatomic potential,Molecular dynamics,Sb2Te3
更新于2025-09-09 09:28:46
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Radiation Resistance of (HgSe)3(In2Se3)<Mn>
摘要： We present the results of studies of the effect of electron irradiation on the electrophysical parameters of (HgSe)3(In2Se3)<Mn> crystals, which are semimagnetic semiconductors with stoichiometric vacancies. It is shown that irradiation of (HgSe)3(In2Se3)<Mn> with high-energy electrons (Ee = 10 MeV, dose D = 1016 cm–2) has little effect on the electrophysical and magnetic properties, which indicates their high radiation resistance.
关键词： cluster,magnetic susceptibility,crystal,electrical conductivity
更新于2025-09-09 09:28:46
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Cotton fabric finished by PANI/TiO2 with multifunctions of conductivity, anti-ultraviolet and photocatalysis activity
摘要： Polyaniline/titanium dioxide (PANI/TiO2) were co-doped with sulfosalicylic (SSA) and sodium dodecyl benzene sulfonate (SDBS) and then deposited onto the surface of cotton fabrics in one-step in-situ polymerization. PANI/TiO2 composites were confirmed by Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), while the surface morphologies of the cotton fabrics were observed by field emission scanning electron microscopy (FESEM). The conductivity of prepared PANI/TiO2/cotton composites was measured by four-probe method and results showed that it decreased slightly with the increase of TiO2 concentration. The conductivity would be up to 8.8 S/cm at concentration of TiO2 4 g/L. The UPF value of PANI/TiO2/cotton composites was significantly enhanced, even if after washing for 10 times. The photocatalytic results showed that absorption and degradation efficiency of PANI/TiO2/cotton composites to rhodamine B (RHB) could reach up to 87.67%, which might be due to the synergistic effects of PANI and TiO2.
关键词： Conductivity,Cotton,Anti-ultraviolet,Polyaniline,TiO2,Photocatalysis activity
更新于2025-09-09 09:28:46