scholarly journals The electrical conductivity of thin metallic films I—Rubidium on pyrex glass surfaces

1936 ◽  
Vol 157 (891) ◽  
pp. 311-330 ◽  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Film Thickness ◽  
High Vacuum ◽  
Mean Free Path ◽  
Metallic Films ◽  
Bulk Metal ◽  
Modern Technique ◽  
Glass Surfaces

This paper describes measurements of the resistivity of thin films of rubidium, deposited on cooled pyrex surfaces by a method which allows the use of the conditions of purity and high vacuum possible with modern technique. In this work, by vigorous heat treatment in high vacua, clean pyrex surfaces have been obtained on which stable and coherent films as thin as 40 A. have been produced. Conductivities have been obtained with a number of atoms on the surface corresponding to less than the number contained in a monatomic layer of rubidium; moreover, the approach of thicker films to the resistivity of the bulk metal is in agreement with that calculated from a simple theory which takes account of the fact that the film thickness is less than the normal electronic mean free path in the bulk metal.

scholarly journals The electrical conductivity of thin metallic films II— caesium and potassium on pyrex glass surfaces

1937 ◽  
Vol 158 (895) ◽  
pp. 718-728 ◽  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Alkali Metals ◽  
Pyrex Glass ◽  
Metallic Films ◽  
Similar Investigation ◽  
The Stability ◽  
Glass Surfaces ◽  
Conductivity Of Thin Films

An account of an investigation of the electrical conductivity of thin films of rubidium deposited in high vacua on very clean glass surfaces has been previously published. It will be referred to in what follows as Part I. The method has now been used in a similar investigation using caesium and potassium. The vigorous heat treatment of the surface and vacuum technique described in Part I has again been found necessary in order to attain reproducible results, and the effects on contaminated surfaces are similar. It will be seen that the resistivities of the stable films are consistent with the theory given in Part I; moreover, the greater stability of the caesium films has supplied a test of the theory down to thicknesses of only a few A. The decay phenomena associated with the unstable films show a marked gradation through these three alkali metals, the stability of a given film increasing in the order potassium—rubidium—caesium.

scholarly journals The electrical conductivity of thin films of mercury

1939 ◽  
Vol 172 (951) ◽  
pp. 530-539 ◽  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Alkali Metals ◽  
High Vacuum ◽  
Experimental Measurements ◽  
Preliminary Note ◽  
Extended Study ◽  
Temperature Coefficients ◽  
Conductivity Of Thin Films

In the present paper an account is given of experimental measurements on the electrical conductivity of thin films of mercury prepared by evaporative deposition in a high vacuum according to the technique described in previous papers (Lovell 1936; Appleyard and Lovell 1937). In a brief preliminary note (Appleyard 1937) we have pointed out that the results for mercury are very different from those for the alkali metals, and that in particular a considerable thickness of mercury must be deposited on the pyrex surface before conductivity begins. We have since confirmed and extended these observations, obtained accurate absolute values for the thickness of the films, investigated their stability, and made an extended study of their temperature coefficients after heat treatment. A comparison with the results of previous workers is given later.

scholarly journals Effect of Grain Size and Film Thickness on the Thermoelectric Properties of Flexible Sb2Te3 Thin Films

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Pornsiri Wanarattikan ◽  
Piya Jitthammapirom ◽  
Rachsak Sakdanuphab ◽  
Aparporn Sakulkalavek
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Film Thickness ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Flexible Substrate ◽  
Rf Magnetron Sputtering ◽  
Mean Free Path

In this work, stoichiometric Sb2Te3 thin films with various thicknesses were deposited on a flexible substrate using RF magnetron sputtering. The grain size and thickness effects on the thermoelectric properties, such as the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and thermal conductivity (k), were investigated. The results show that the grain size was directly related to film thickness. As the film thickness increased, the grain size also increased. The Seebeck coefficient and electrical conductivity corresponded to the grain size of the films. The mean free path of carriers increases as the grain size increases, resulting in a decrease in the Seebeck coefficient and increase in electrical conductivity. Electrical conductivity strongly affects the temperature dependence of PF which results in the highest value of 7.5 × 10−4 W/m·K2 at 250°C for film thickness thicker than 1 µm. In the thermal conductivity mechanism, film thickness affects the dominance of phonons or carriers. For film thicknesses less than 1 µm, the behaviour of the phonons is dominant, while both are dominant for film thicknesses greater than 1 µm. Control of the grain size and film thickness is thus critical for controlling the performance of Sb2Te3 thin films.

scholarly journals Enhanced Ionic Conduction at the Film/Substrate Interface in LiI Thin Films Grown on Sapphire(0001)

1993 ◽  
Vol 318 ◽  
Author(s):  
D. Lubben ◽  
F. A. Modine
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Ionic Conduction ◽  
High Vacuum ◽  
Dislocation Motion ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Substrate Interface ◽  
Interdigital Electrodes ◽  
Film Substrate

ABSTRACTThe ionic conductivity of LiI thin films grown on sapphire(0001) substrates has been studied in situ during deposition as a function of film thickness and deposition conditions. LiI films were produced at room temperature by sublimation in an ultra-high-vacuum system. The conductivity of the Lil parallel to the film/substrate interface was determined from frequency-dependent impedance measurements as a function of film thickness using Au interdigital electrodes deposited on the sapphire surface. The measurements show a conduction of ∼5 times the bulk value at the interface which gradually decreases as the film thickness is increased beyond 100 nm. This interfacial enhancement is not stable but anneals out with a characteristic log of time dependence. Fully annealed films have an activation energy for conduction (σT) of ∼0.47 ± .03 eV, consistent with bulk measurements. The observed annealing behavior can be fit with a model based on dislocation motion which implies that the increase in conduction near the interface is not due to the formation of a space-charge layer as previously reported but to defects generated during the growth process. This explanation is consistent with the behavior exhibited by CaF2 films grown under similar conditions.

STUDY OF SUPERCONDUCTING Y-BA-CU-O THIN FILMS WITH ZERO RESISTANCE TEMPERATURE AT 77K

1987 ◽  
Vol 01 (02) ◽  
pp. 571-574
Author(s):  
Jia-qi Zheng ◽  
Guo-guang Zheng ◽  
Dong-qi Li ◽  
Wei Wang ◽  
Jin-min Xue ◽  
...  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electron Beam ◽  
High Vacuum ◽  
Vacuum System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zero Resistance

Y-Ba-Cu-O thin films are deposited onto severval kinds of substrates by electron beam evaporating in a high vacuum system. After the heat treatment at 850–890°c for 1hr the Y-Ba-Cu-O films on the BaF2 substrates show superconducting behaviors with the midpoint Tc around 87K and zero resistance temperature at 77K. The composition and stucture analysis of these films have been studied by AES, XRFS and x-ray diffraction.

scholarly journals Temperature Dependence of the Hall Coefficient of Thin Films

1979 ◽  
Vol 6 (1) ◽  
pp. 19-22
Author(s):  
C. R. Tellier ◽  
C. Pichard ◽  
A. J. Tosser
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Free Path ◽  
Hall Coefficient ◽  
Mean Free Path ◽  
Theoretical Expression ◽  
Metallic Films ◽  
Conduction Model ◽  
The Mean

A theoretical expression for the temperature coefficientβRHof the Hall coefficientRHFof metallic films is deduced from the Fuchs–Sondheimer conduction model. The general expression takes into account the deviation introduced by the geometrical limitation of the mean free path. This is negligible for relatively thick films (k≥ 1 forp= 0) and agrees with experiments previously reported by other authors.

scholarly journals Epitaxial Growth and Optical Properties of Laser Deposited CdS Thin Films

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Atef S. Gadalla ◽  
Hamdan A. S. Al-shamiri ◽  
Saad Melhi Alshahrani ◽  
Huda F. Khalil ◽  
Mahmoud M. El Nahas ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Photon Energy ◽  
Hexagonal Phase ◽  
High Vacuum ◽  
Structural Features ◽  
Film Deposition ◽  
X Ray ◽  
Cds Thin Films ◽  
Cds Films

In this study, cadmium Sulfide (CdS) thin films were synthesized on quartz substrates using an infrared pulsed laser deposition (IR-PLD) technique under high vacuum (~10−6 Torr) conditions. X-ray diffraction was used to evaluate the structural features. According to X-ray analysis, the deposited CdS films are crystalline and have a favored orientation on a plane (110) of an orthorhombic. The peak intensity and the average crystallite size increases with increasing the film thickness. After annealing at 300 °C, the orthorhombic phase transformed into a predominant hexagonal phase and the same result was obtained by SEM photographs as well. Spectrophotometric measurements of transmittance and reflectance of the CdS films were used to derive optical constants (n, k, and absorption coefficient α). The optical band gap energy was found to be 2.44 eV. The plasma plume formation and expansion during the film deposition have also been discussed. The photocurrent response as a function of the incident photon energy E (eV) at different bias voltages for different samples of thicknesses (85, 180, 220 and 340 nm) have been studied, indicating that the photocurrent increases by increasing both the film thickness and photon energy with a peak in the vicinity of the band edge. Thus, the prepared CdS films are promising for application in optoelectronic field.

A Comparison of Magnetic Properties of Thin Films of Fe/GaAs(100) and Ni/MICA

1992 ◽  
Vol 280 ◽  
Author(s):  
Bruce Andrien ◽  
David Miller
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Gaas Substrate ◽  
High Vacuum ◽  
Auger Spectroscopy ◽  
Ultra High Vacuum ◽  
In Situ Adsorption

ABSTRACTA comparison between the morphology and magnetic properties has been made with thin films of Fe grown on GaAs(lOO) and of Ni grown on natural mica in the 10Å to 1000Å thickness range, in ultra high vacuum. The films are characterized in-situ by Auger spectroscopy and by an in-situ UHV M/H hysteresis loop tracer. If the films are thermally annealed, above 550°C for less than a few seconds, the film morphology changes. The Fe films form surface assembled clusters which are epitaxial with the GaAs substrate with diameters of order of the original average film thickness, while the Ni films grow large grains. The Auger signals show that the Fe clustering exposes the GaAs substrate while the Ni films are continuous and cover the mica substrate. In-situ adsorption studies of CO on the Ni films were consistent with the continuous nature of the Ni films. Hysteresis M/H curves are taken as a function of thickness and plots of coercivity versus film thickness or average cluster size shows a maximum near 100Å for both the Ni and the Fe films. The maximum is believed to be due to a trade-off between super-paramagnetism and magnetostatic forces, but with the grains in the Ni film playing the role of the clusters in the Fe film.

The conductivity of thin metallic films according to the electron theory of metals

1938 ◽  
Vol 34 (1) ◽  
pp. 100-108 ◽  
Author(s):  
K. Fuchs
Keyword(s):  
Thin Films ◽  
Alkali Metals ◽  
Metallic Films ◽  
Electron Theory ◽  
Bulk Metal ◽  
Conduction Electrons ◽  
Physical Laboratory ◽  
Simplifying Assumptions ◽  
The Mean ◽  
Conductivity Of Thin Films

The conductivity of thin films of the alkali metals has recently been measured in the H. W. Wills Physical Laboratory, Bristol*. It was found that as the thickness of the film is decreased to that of a few atomic layers the conductivity drops below that of the bulk metal. In the papers quoted the hypothesis was put forward that this effect is due to the shortening of the mean free paths of the conduction electrons of the metal by collisions with the boundaries of the film. The experimental results were compared with a formula derived on the basis of this hypothesis. This formula was, however, obtained subject to a number of simplifying assumptions, and it is the first purpose of this paper to obtain a more accurate formula. I also compare this formula with experiment, and make certain deductions about the surfaces of thin films.

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