Properties Of Conductive Films Research Articles

Влияние различных типов растворителей на морфологию, оптические и проводящие свойства плёнок PCBM

The article deals with the influence of various types of solvents on the spectral characteristics and conductive properties of films [6,6]-methyl phenyl-C61-butyric acid, precipitated from solutions. It is clearly shown that the effect of the nature of the solvent affects the morphology of the film surface. Analysis of the spectra of the optical range showed the presence of a maximum of the absorption coefficient in the frequency range of 340-490 nm. The calculation of the optical bandgap clearly demonstrates the possibility of modernizing the atomic structure of films by using various types of solvents. A study of the current-voltage characteristics showed the presence of a photocurrent in carbon films deposited with dichloromethane, toluene, and chloroform.

Improvement of transparent conductive properties of Cu films by introducing H2 into deposition atmosphere during RF magnetron sputtering

Abstract Different thicknesses (2–250 nm) of Cu films were deposited on glass substrate by RF magnetron sputtering in Ar and Ar + H2 atmospheres at room temperature. It is found that crystallinity and conductive properties of the films enhance but visible light transmittance (TVis) decreases with increase of film thickness. Compared with the Cu films deposited in Ar, those deposited in Ar + H2 have higher crystallinity and surface roughness, and they have better conductive properties and higher TVis at film thickness above 5 nm. Overall, the Cu films deposited in Ar and Ar + H2 can be achieved higher figure of merit (FOM) in a thickness range of 3~5 and 5~8.5 nm, respectively. Furthermore, the higher FOM values of Cu film deposited in Ar + H2 atmosphere are higher than those of Cu film deposited in Ar atmosphere. The correlation between the improvement of transparent conductive properties of Cu films and modification of film microstructure due to introduction of H2 into deposition atmosphere is discussed.

Chemical solution deposition and characterization of the La1-хSrxScO3-α thin films on La1-xSrxMnO3-α substrate

The development of solid oxide fuel cells (SOFC) is one of the priority directions for the creation of alternative energy sources. High operating temperatures of these devices are lead to the complexity of the constructions and active diffusion processes between the functional materials. The use of thin-film proton electrolytes is a promising way to reduce the operating temperature of SOFC, while the conductivity level and, as a result, the effective power, may be maintained due to the smaller thickness of the film.Based on LaScO3 proton-conducting oxides with a perovskite structure, having high chemical stability to water vapor, are promising proton electrolytes for SOFC, but they are poorly studied in the form of thin films. Lanthanum-strontium manganite is one of the most common materials for the SOFC cathode. The aim of this work is to study the effect of the La0.6Sr0.4MnO3-α cathode substrate composition on the properties, including the electrical conductivity of La1-xSrxScO3 (0.01, 0.05 and 0.10) thin-film proton electrolytes, obtained by simple centrifugation of the film-forming solution. The properties of La1-xSrxScO3 in the form of ceramic and thin-film samples are compared.The experiment showed that the films La1-xSrxScO3 at 5 ÷ 30-fold deposition on cathode substrates form continuous coatings with a grain size of 50–200 nm, which do not contain transverse pore. These results have a fundamental importance for the development of SOFC with ultra-thin film electrolyte on a supporting electrode. It is established that under dry and wet air the electrical conductivity of La0.6Sr0.4MnO3-α/La1-xSrxScO3/Pt cells is bulk conductivity and it rises with increasing atmospheric humidity, which indicates an increase in the contribution of proton conductivity. In this case, the grain-boundary resistance of the material and the polarization resistance of the electrodes are practically not realized. The conductivity of LSS films is 1–2 orders of magnitude higher than the bulk conductivity of ceramic samples of similar composition and has a low activation energy. The observed differences in the conductive properties of films are explained by the interaction of related perovskites of the scan date and lanthanum manganite.The data obtained may be of interest to specialists in the fields of hydrogen energy, electrochemistry, materials science, the development of electrochemical devices: sensors, fuel cells.

The Influence of Physical Properties of ZnO Films on the Efficiency of Planar ZnO/Perovskite/P3HT Solar Cell

ZnO thin films prepared by pulsed laser deposition at low temperature are utilized as the electron transport layer in CH3NH3PbI3−xClx‐based perovskite solar cells with a planar heterojunction structure. Oxygen pressure greatly influences the transparent and conductive properties of ZnO films, which are extremely important as electron transport layer for the perovskite solar cells. The transparent and conductive properties of the films under different oxygen pressures are studied by ultraviolet‐visible spectrophotometer and Hall effect measurement system. Through controlling the oxygen pressure, transparent ZnO films with high conductivity are grown and adopted as electron transport layer for planar perovskite solar cell with a power conversion efficiency of 6.3%. After further surface modification of ZnO electron transport layer with [6,6]‐phenyl‐C61‐butyric acid methyl ester, the efficiency of the planar solar cell increases to 7.5%.

Emission and conductive properties of polyaniline thin films

Thin films of polyaniline were obtained by thermal vacuum deposition of the Knudsen effusion. Conductive properties of the films were studied as a function of deposition conditions. It is experimentally shown an increase in the emissivity of tungsten tip coated with polyaniline film of nano-dimensional thickness, and a model of the observed effect is considered.

Supramolecular Structure and Conductive Properties of Dielectric Polymers in Metal/Polymer/Metal Systems

The influence of weight-average-molecular weight (M w ) on the maximal thickness (h ) of the films of polystyrenes (PSs) and poly(methyl methacrylate)s (PMMAs) possessing the level of metal conductivity has been investigated. It has been shown that h is directly proportional to M for both PSs, and PMMAs. This behavior implies the value of h is governed by the size of the random coil of these polymers. These results have been compared with those obtained earlier for other dielectric polymers, and discussed with respect to the influence of the nature of the solvent on the conductive properties of films of dielectric polymers.

Optical and Conductivity Properties of Films from Liquid-Phase Exfoliation of Natural Graphite

We experimentally determine the conductivity and optical transmittance of graphite layers, obtained from the liquid phase exfoliation of natural crystalline graphite. The measured transmittance values range from 0.9 to 0.97, comparable to the theoretical transmittance of graphene. In the low frequency limit the conductivity of the films follows the percolation model for two-dimensional networks. Solution processed graphene materials are attractive for applications as conductive transparent films and scalable graphene devices.

A MODEL FOR A RESISTIVE SWITCH MEMORY CELL WITH RECHARGEABLE SPACE CHARGE

ABSTRACT An advanced leakage current model combining the electronic carrier injection/ejection at the electrode interfaces (described by thermionic emission) with the film conduction properties of a thin dielectric film (modelled as wide band gap semiconductor) is used to describe the current-voltage (I-V) curve of a flash-like resistive switch memory cell. Such a cell consists of a metal-insulator-metal capacitor structure with some embedded charge storage elements within the dielectric, e.g. a floating electrode (like in the gate of a “Flash”) or some metallic ions or clusters, which can be charged or discharged by an applied voltage or current or by a “redox” reaction. The resulting different conductance levels can be used for a resistive switching memory cell. This contribution presents calculated simulation results on I-V curves in dependence on polarity and concentration of the stored charge as well as on other parameters such as dielectric constant, background homogeneous defect densities in the dielectric and electrode properties. These parameters show a large influence on the switching ratio S = R(high)/R(low), an important parameter for the application in a device.

A Leakage Current Model for “Flash-like”, Non-Volatile Resistive Switch Memory Cell

ABSTRACTAn advanced leakage current model combining the electronic carrier injection /ejection at the electrode interfaces (described by thermionic emission) with the film conduction properties of a thin dielectric film (modelled as wide band gap semiconductor) is used to describe the current-voltage (I-V) curve of a flash-like resistive switch memory cell. Such a cell consists of a metal-insulator-metal capacitor structure with some embedded charge storage elements within the dielectric, e.g. a floating electrode (like in the gate of a “Flash”) or some metallic ions or clusters, which can be charged or discharged by an applied voltage or current. The resulting different conductance levels can be used for a resistive switching memory cell. This contribution presents calculated simulation results on I-V curves in dependence on polarity and concentration of the stored charge as well as on other parameters such as dielectric constant, background homogeneous defect densities in the dielectric and electrode properties. These parameters show a large influence on the switching ratio S = R(high) / R(low), an important parameter for the application in a device.

Correlations between morphology and conductivity properties of films of polyaniline

Films of polyaniline (PANI) have been prepared using laser-assisted deposition (LAD). The morphology of these films has been examined using low-angle X-ray diffraction, scanning electron microscopy and atomic force microscopy. The films exhibit dense packing and better ordering of polymer strands as compared with films prepared using electrochemical deposition. The sheet resistance has been measured by the four-probe method and decreases with increasing temperature. The films exhibit better conductivity in the morphologically ordered state. Copyright © 1999 John Wiley & Sons, Ltd.

Space-charge influenced-injection model for conduction in Pb(ZrxTi1−x)O3 thin films

A comprehensive study of leakage conduction in Pb(ZrxTi1−x)O3films with Pt electrodes is carried out. The conduction properties of films prepared in different ways (sol–gel coating, metalorganic chemical vapor deposition, sputtering) were studied by using different experimental techniques including variation of the applied voltage profile, photoassisted measurements, measurements at elevated temperatures, and variation of the prehistory of the samples. Based on the collective data, it is concluded that two different regimes of carrier injection (with the critical electric field of the crossover between these regimes being independent of the measuring technique) are responsible for true leakage conduction in Pt–Pb(ZrxTi1−x)O3–Pt films. A space-charge influenced-injection model is proposed for the interpretation of the experimental results obtained. This model describes well the main features of the observed current–voltage characteristics and provides a reasonable fit for the current–voltage curves measured at elevated temperatures, the values of the fitting parameters being in good agreement with the results of other studies. The true leakage current in the Pt–Pb(ZrxTi1−x)O3–Pt system is shown to be time dependent because of the influence of the injected charge entrapment during measurement. According to the present results, an activation energy of about 0.9 eV describes the temperature dependence of conduction in the range of 70–200 °C. It is shown that a possible origin of the crossover in the activation energy at the temperature range 120–140 °C widely reported in the literature can be a consequence of the measuring procedure.

Grain Size Distribution and Degree of Texture in Films Used in Integrated Circuits

AbstractAs miniaturisation proceeds, the electrical properties of conductive films used in modem IC's are increasingly influenced by the grain sizes and the texture of the films. There is a need therefore to devise techniques which can examine these properties. Described in this work are two new cross-sectional TEM techniques for use on fully-processed IC's to determine quantitatively grain size distributions and the degree of texture in a film. The technique which investigates texture is used to determine how quickly the texture develops through a polysilicon film.

Field-Effect Transistor based on conducting Langmuir-Blodgett films of EDTTTF derivatives

A Field-Effect Transistor in which the channel is made of Langmuir-Blodgett layers of EDTTTF derivatives is described and studied. The device behaves as a P-channel MOSFET working in the depletion mode. A deep modulation of the film conduction properties and non-linear contact resistance effects have been observed.

Properties of conductive films made from fine spherical silver-palladium alloy particles

Silver-palladium alloy films were made by a thick-film technique using several metal powders prepared by the spray-pyrolysis method. Two types of powders were used: silver-palladium alloy powders (15 mol % Pd and 30 mol % Pd) and mixtures of silver and palladium powders. The fired films were about 2–3 Μm in thickness. The alloy particles sintered uniformly in firing, whereas, in the case of the powder mixtures, the alloying of silver and palladium particles caused uneven particle growth and large voids were formed in the fired films. For this reason the films made from the alloy powders had better conductive properties than those made from the powder mixtures. The resistivities of the films made from the alloy powders were close to the intrinsic value for silver-palladium alloys. Further, the oxidation of palladium during heating in air was significantly suppressed in the alloy powders when the palladium content was lower than 30 mol % in accordance with thermodynamic considerations.

A Theoretical Study of the Effect of Elastic Strain on the Electrical Resistance of Thin Metal Films

Theoretical equations for the strain coefficient of resistance in metallic thin films are derived. The films considered range from ultrathin, discontinuous films of theoretical average thickness of less than an angstrom to relatively thick films of about 6000 Å which exhibit bulk material properties. The films are classified into five thickness ranges according to the predominating conduction mechanisms. It is found that ultrathin films exhibit strain sensitivity of two orders of magnitude higher than the bulk metal. The sensitivity reduces with increasing average film thickness to a minimum value which occurs in the transition region in which the film conduction properties change from those of a semiconductor to those of a metal. With further increase in thickness the bulk value of sensitivity is approached. The theory is compared with experimental studies and possible misinterpretations in previous studies are discussed.