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1.
《中国物理 B》2015,(11)
The discovery of an extraordinarily superconductive large energy gap in SrTiO3 supported single-layer Fe Se films has recently initiated a great deal of research interests in surface-enhanced superconductivity and superconductive ultrathin films fabricated on crystal surfaces. On account of the instability of ultra-thin films in air, it is desirable to perform electrical transport measurement in ultra-high vaccum(UHV). Here we review the experimental techniques of in situ electrical transport measurement and their applications on superconductive ultrathin films. 相似文献
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LISICON thin films have been prepared with RF sputtering and subsequent heat-treatment. The crystal phases of sputtered films depend on the sputtering conditions, especially the target composition and ambient gas atmosphere. Though the as-sputtered films in Ar-O2 mixed gas (target composition: Li3Zn0.5GeO4+0.5 ZnO, gas pressure: 9×10-2 Torr, oxygen gas content: 74.6%) were amorphous; LISICON single phase thin films were obtained after annealing at 600°C for 6 h. The conductivity of the film at 500°C is 5×10-3ω-1cm-1 which is slightly lower than that for ceramic Li3Zn0.5GeO4. 相似文献
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《Solid State Ionics》2006,177(26-32):2513-2518
Ceria-based thin films are potential materials for use as gas-sensing layers and electrolytes in micro-solid oxide fuel cells. Since the average grain sizes of these films are on the nanocrystalline scale (< 150 nm), it is of fundamental interest whether the electrical conductivity might differ from microcrystalline ceria-based ceramics. In this study, CeO2 and Ce0.8Gd0.2O1.9−x thin films have been fabrication by spray pyrolysis and pulsed laser deposition, and the influence of the ambient average grain size on the total DC conductivity is investigated. Dense and crack-free CeO2 and Ce0.8Gd0.2O1.9−x thin films were produced that withstand annealing up to temperatures of 1100 °C. The dopant concentration and annealing temperature affect highly the grain growth kinetics of ceria-based thin films. Large concentrations of dopant exert Zener drag on grain growth and result in retarded grain growth. An increased total DC conductivity and decreased activation energy was observed when the average grain size of a CeO2 or Ce0.8Gd0.2O1.9−x thin film was decreased. 相似文献
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N. N. Polyakov 《Russian Physics Journal》1991,34(1):60-64
A method is proposed for determining the components of the electrical conductivity tensor of anisotropic semiconductor specimens of rectangular form. Expressions are obtained which allow use of computer technology for processing experimental results. The technique is justified theoretically by solving the corresponding electrodynamic boundary problem, and the error involved in approximating thin films and point contacts is evaluated. Results of an experimental test of the proposed method are presented.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 73–77, January, 1991. 相似文献
6.
Stable homogeneous amorphous alloy1 films of Ge with different concentrations of Al, Cu and Fe have been prepared by the simultaneous vapor deposition technique. Ge-Metal films are amorphous up to a concentration of ~ 40 at.% Al, ~ 20 at.% Cu and ~ 20 at.% Fe. The cyclic annealing and crystallization temperature of these films show that whereas Al increases the stability of the amorphous phase, the addition of Cu and Fe decreases it. The electrical resistivity decreases gradually with increasing Al content. In contrast, a rapid decrease in the electrical resistivity is observed for the Ge-Cu and Ge-Fe systems. The thermoelectric power (TEP) of Ge-Cu and Ge-Fe system assumes small values ~ few μV/deg for concentrations greater than few atomic percent. Ge-Al system exhibits large positive thermoelectric power at all compositions. The temperature dependence of the electrical resistivity of these alloy films show that the addition of Cu and Fe to Ge results in a drastic decrease in the activation energy of conduction whereas the addition of Al increases the activation energy. Ge-Al films exhibit intrinsic like conduction in the temperature range 100–300 K. The Ge-Cu and Ge-Fe films exhibit hopping conduction from 100–300 K and the related density of states is up to 100 times larger than in pure a-Ge films. 相似文献
7.
Resistive transitions of niobium films evaporated onto the substrate at cryogenic temperatures have been investigated. The Maki-Thompson term gives a contribution to the excess electrical conductivity of highly disordered Nb film. 相似文献
8.
D. Ning Q. H. Lou J. X. Dong Y. R. Wei 《Applied Physics A: Materials Science & Processing》1996,62(6):509-512
After being irradiated in air by a XeCI (308 nm) excimer laser, the electrical conductivity of solid thin-film C60 has been improved by more than six orders of magnitudes. The products resulting from laser irradiation of C60 films have been investigated by Raman scattering and the onset of conductivity can be attributed to laser-induced oxygenation and disintegration of the fullerene. Irradiated by 40 ns laser pulses with different fluence, products with different microstructure were observed. At lower fluence, the Raman features of microcrystalline graphite and fullerene polymer were observed. At a fluence just below the ablation threshold (36 mJ/cm2), the fullerene molecules in the film were disintegrated completely and transformed to amorphous graphite. 相似文献
9.
M. N. Gerke A. V. Istratov D. N. Bukharov O. A. Novikova I. O. Skryabin S. M. Arakelian 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(12):1387-1390
The surface resistance of bimetallic granular films prepared by means of laser-induced deposition is studied. The possibility of modeling their conductivity is demonstrated, depending on their morphological properties. 相似文献
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Additional structure is seen in conductance versus voltage curves when electrons are tunneled into very thin superconducting films. This peak like structure has been detected in several materials; it is observed at multiples of the energy gap above the main conductance maximum. The peak amplitude is very thickness dependent. At roughly half the transition temperature of the ultrathin film the amplitude goes to zero within a narrow temperature range. Effects of magnetic field, an overlay of a non-superconductor, and annealing are less pronounced. The most probable explanation seems to be a model where the tunneling rate is stimulated whenever the relaxation and recombination phonon frequencies equal.Supported by the Swedish Natural Science Research Council. 相似文献
13.
Lead films vapor quenched onto nucleating monolayers of Mo or W exhibit strong lattice disorder and can be considered to be amorphous. The amorphous-to-crystalline transformation temperatureT
tr is indicated by a sharp drop of the electrical resistivity in the course of annealing.T
tr is found to be proportional tod
–2 for Pb thicknessd smaller than 30 nm. The superconducting transition temperatureT
c is by 0.6 to 1 K smaller in the amorphous state than after crystallization. In both states,T
c is proportional tod
–1. Prenucleation with about half a monolayer of Mo leads to quite the sameT
c depression as observed earlier by Strongin et al. on Pb films vapor quenched onto predeposited films of SiO, Ge or Al2O3. For comparison, experiments have been carried out with 2.5 nm Ge predeposits. As with Mo prenucleation, a well defined transformation temperatureT
tr of about the same value has been observed.T
c of bulk amorphous Pb can be extrapolated to be about 6.6 K. 相似文献
14.
The optical absorption edge of CuGaTe2 thin films in the energy range 1 to 2·3 eV was studied. The characteristic band gaps were found to be 1·23 eV and 1·28 eV
whereas the acceptor ionization energy was 170 meV. Electrical conductivity measurements were carried out in the temperature
range 300–550 K and two acceptor states with ionization energies 400 meV and 140 meV were found. The origin of acceptor states
is explained based on covalent model. 相似文献
15.
The influence of hydrogenation on electrical conductivity of vanadium dioxide thin films has been investigated. It has been
shown using measurements of the electrical conductivity that the hydrogenation of vanadium dioxide thin films leads to a decrease
in the temperature of the phase transition from the tetragonal phase (with “metallic” conductivity) to the semiconducting
monoclinic phase. It has been found that, upon doping of vanadium dioxide with hydrogen, the electrical conductivity of the
monoclinic phase can increase by several orders of magnitude. Nonetheless, the temperature dependence of the electrical conductivity
of hydrogenated films exhibits a typical semiconducting behavior in the temperature range where the monoclinic phase is stable. 相似文献
16.
K. A. Verkhovskaya A. A. Plakseev I. D. Gavrilova A. M. Lotonov S. G. Yudin 《Moscow University Physics Bulletin》2010,65(4):307-310
Based on the study of dielectric dispersion for 2-nm-thick Langmuir films made of an poly(vinylidenefluoride-trifluoroethylene)
P(VDF-TrFE) copolymer, we demonstrated the existence of two simultaneously developing relaxation processes. It was shown that
Langmuir-Blodgett films are conducting. 相似文献
17.
Leonid V. Dekhtyaruk 《Central European Journal of Physics》2006,4(1):73-86
The annealing-time dependence of the electrical conductivity of multilayered single-crystal and polycrystalline metal films
has been analyzed theoretically within the frame of the semi-classical approach. It is demonstrated that changes in the electrical
conductivity which are caused by the diffusion annealing allow for investigating the processes of the bulk and grain-boundary
diffusion, and for estimating the coefficients of the diffusion. The electrical conductivity was calculated and the numerical
analysis of the diffusion-annealing time dependence was performed at various parameters. 相似文献
18.
Y. Shi C. M. Xiong X. S. Wang C. H. Lei H. X. Guo X. J. Fan 《Applied Physics A: Materials Science & Processing》1996,63(4):353-357
Polycrystalline C60 films are deposited onto a variety of substrates by ionized cluster beam deposition (ICBD) technique. The structure of the ICBD C60 films are studied by transmission electron microscopy (TEM). The electrical characteristics of the ICBD C60 films on silicon substrates are investigated by current-voltage (I–V) measurements. TheICBD C60/p-Si and C60/n-Si heterostructures show strong current rectification, which is analyzed using band theory. 相似文献
19.
The structure and thickness of zinc and cadmium chalcogenide semiconductor films are studied by X-ray radiography. The film thickness is shown to be comparable with the half-value layer depth. The electrical conductivity of the films increases upon heating in the hydrogen atmosphere and decreases upon heating in carbon oxide. The opposite trend is observed in the ratio between the electrical conductivity and band gap of the initial and oxidized film surfaces.
相似文献20.