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271.
We examine the effect of cations in solutions containing benzotriazole (BTA) and H202 on copper chemical mechanical polishing (CMP). On the base of atomic force microscopy (AFM) and material removal rate (MRR) results, it is found that ammonia shows the highest MRR as well as good surface after CMP, while KOH demonstrates the worst performance. These results reveal a mechanism that small molecules with lone-pairs rather than molecules with steric effect and common inorganic cations are better for copper CMP process, which is indirectly confirmed by open circuit potential (OCP). 相似文献
272.
Growth Related Carrier Mobility Enhancement of Pentacene Thin-Film Transistors with High-k Oxide Gate Dielectric 下载免费PDF全文
Carrier mobifity enhancement from 0.09 to 0.59cm2/Vs is achieved for pentacene-based thin-film transistors (TFTs) by modifying the Hf02 gate dielectric with a polystyrene (PS) thin film. The improvement of the transistor's performance is found to be strongly related to the initial film morphologies of pentacene on the dielectrics. In contrast to the three-dimensional island-like growth mode on the HI02 surface, the Stranski- Krastanov growth mode on the smooth and nonpolar PS/HfO2 surface is believed to be the origin of the excellent carrier mobility of the TFTs. A large well-connected first monolayer with fewer boundaries is formed via the Stranski-Krastanov growth mode, which facilitates a charge transport parallel to the substrate and promotes higher carrier mobility. 相似文献
273.
I. Ruiz de Larramendi R. López-Antón J. I. Ruiz de Larramendi T. Rojo 《Applied Physics A: Materials Science & Processing》2008,93(3):655-661
Polycrystalline samples of Pr1−x
Sr
x
Fe0.8Co0.2 O3−δ
(x=0.1, 0.2, 0.3) (PSFC) were prepared by the combustion synthesis route at 1200°C. The structure of the polycrystalline powders
was analysed with X-ray powder diffraction data. The X-ray diffraction (XRD) patterns were indexed as the orthoferrite similar
to that of PrFeO3 having a single-phase orthorhombic perovskite structure (Pbnm). Pr1−x
Sr
x
Fe0.8Co0.2O3−δ
(x=0.1, 0.2, 0.3) films have been deposited on yttria-stabilized zirconia (YSZ) single-crystal substrates at 700°C by pulsed
laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes. The structure of the films was analysed
by XRD, scanning electron microscopy (SEM) and atomic force microscopy (AFM). All films are polycrystalline with a marked
texture and present pyramidal grains in the surface with different size distributions. Electrochemical impedance spectroscopy
(EIS) measurements of PSFC/YSZ single crystal/PSFC test cells were conducted. The Pr0.7Sr0.3Fe0.8Co0.2O3−δ
film at 850°C presents a lower area specific resistance (ASR) value, 1.65 Ω cm2, followed by the Pr0.8Sr0.2Fe0.8Co0.2O3−δ
(2.29 Ω cm2 at 850°C) and the Pr0.9Sr0.1Fe0.8Co0.2O3−δ
films (5.45 Ω cm2 at 850°C). 相似文献
274.
TEM,XRD and AFM study of poly(<Emphasis Type="Italic">o</Emphasis>-ethoxyaniline) films: new evidence for the formation of conducting islands 总被引:1,自引:0,他引:1
Fabio L. Leite William F. Alves Mirta Mir Yvonne P. Mascarenhas Paulo S. P. Herrmann Luiz H. C. Mattoso Osvaldo N. OliveiraJr. 《Applied Physics A: Materials Science & Processing》2008,93(2):537-542
The existence of conducting islands in polyaniline films has long been proposed in the literature, which would be consistent with conducting mechanisms based on hopping. Obtaining direct evidence of conducting islands, however, is not straightforward. In this paper, conducting islands were visualized in poly(o-ethoxyaniline) (POEA) films prepared at low pH, using Transmission Electron Microscopy (TEM) and atomic force spectroscopy (AFS). The size of the islands varied between 67 and 470 Å for a pH=3.0, with a larger average being obtained with AFS, probably due to the finite size effect of the atomic force microscopy tip. In AFS, the conducting islands were denoted by regions with repulsive forces due to the double-layer forces. On the basis of X-ray diffraction (XRD) patterns for POEA in the powder form, we infer that the conducting islands are crystalline, and therefore a POEA film is believed to consist of conducting islands dispersed in an insulating, amorphous matrix. From conductivity measurements we inferred the charge transport to be governed by a typical quasi-one dimensional variable range hopping (VRH) mechanism. 相似文献
275.
M. Aoki K. Miwa T. Noritake N. Ohba M. Matsumoto H.-W. Li Y. Nakamori S. Towata S. Orimo 《Applied Physics A: Materials Science & Processing》2008,92(3):601-605
We have investigated the structural and dehydriding properties of Ca(BH4)2. It was found that Ca(BH4)2 undergoes a structural phase transformation from an orthorhombic low-temperature (LT) modification into a tetragonal high-temperature
(HT) modification between 433 K and 523 K. The amount of hydrogen desorbed from Ca(BH4)2 during the pressure–composition (p–c) isotherm measurement was 5.9 mass%. This hydrogen desorption is caused by the partial dehydrogenation of Ca(BH4)2 accompanied by the formation of CaH2 and orthorhombic intermediate phases. 相似文献
276.
S. Speziale R. Jeanloz S. Meenakshi A.K. Verma B.K. Godwal 《Journal of Physics and Chemistry of Solids》2008,69(9):2325-2331
High-pressure angle-dispersive X-ray diffraction measurements show that Cd0.80Hg0.20 alloy remains in the hcp structure up to 50 GPa. We observe subtle anomalies in the pressure variation of the lattice parameters and their ratio, and in normalized stress versus strain. Electronic-structure calculations, as well as experimental and theoretical results for Cd, suggest that these anomalies are related to the occurrence of electronic topological transitions. Our results support Lifshitz's prediction that electronic phase transitions can cause anomalies in structural and elastic properties of materials. 相似文献
277.
Physical properties of a nanocrystalline thin film is greatly influenced by its morphological and structural evolution. We try to understand the transition of SnO2 thin films from amorphous to nanocrystalline structure with XRD, IR, SEM, AFM and surface profiler studies. A 2D layer like structure resulting from quantum confinement is found for the films prepared at 400 °C. We observed a new IR band at 530 cm−1 that was theoretically predicted and report it for the first time. A correlation of population of defects in SnO2 films with change in lattice parameters and FWHM of IR bands are reported. The electric and optical properties of the films have been discussed. 相似文献
278.
The effect of the surface characteristics of Ni catalyst films on the growth behavior of multi-walled carbon nanotubes (MWCNTs) were investigated using Ni catalyst films prepared by different physical vapor deposition methods, electron-beam evaporation and sputtering. The growth behavior of MWCNTs was dependent upon the surface roughness of the Ni films. After a pretreatment process with NH3, the root mean squares of surface roughness of e-beam evaporated and sputtered Ni catalyst films increased to 16.6 and 3.2 nm, respectively. Curled-MWCNTs and carbon-encapsulated Ni nanoparticles were formed on the Ni film deposited by e-beam evaporation while vertically aligned-MWCNTs were grown on the sputter-deposited film. In addition, the surface roughness of the Ni films affected the field emission properties of the MWCNTs. This was considered to originate from the specific growth behavior of the MWCNTs which was primarily caused by the initial surface roughness of the Ni films. 相似文献
279.
Amorphous thin films of TiO2 are irradiated by swift heavy ion (SHI) beam. Surface topography is studied by atomic force microscopy (AFM). Formation of nanosized oblate hillocks on the surface of irradiated films is investigated by AFM studies. After irradiation, amorphous to crystalline phase transition is observed in glancing angle X-ray diffraction (GAXRD) and Raman spectroscopy studies. Photoluminescence (PL)-spectroscopy is carried out for optical characterization. Threshold value necessary for emergence of hillocks is estimated. 相似文献
280.
C2H4 mediations were used to modify the Stranski-Krastanow growth mode of Ge dots on Si(0 0 1) at 550 °C by ultra-high vacuum chemical vapor deposition. With appropriate C2H4-mediation to modify the Si surface, the elongated Ge hut clusters can be transformed to highly uniform Ge domes with a high Ge composition at the core. These C2H4-mediated Ge dots, almost bounded by {1 1 3} facets, have an average diameter and height of 55 and 9 nm, respectively. We propose two major mechanisms to depict the formation of these C2H4-mediated Ge dots: (i) an almost hydrogen-passivated Si surface to limit the nucleation sites for dot formation, and (ii) the incorporation of Ge atoms, repelled by the C-rich areas, into the existing Ge dots. This work provides a useful scheme to tune the topography of Ge dots in an UHV/CVD condition for possible optoelectronic applications. 相似文献