Bismuth and antimony are semimetals. The Bi(1-x)Sbx alloys (0.04&lt;×&lt;0.22) are found to show fair Seebeck coefficient suitable for thermoelectric applications. Bulk Bi85Sb15 alloy was prepared by the melt-quenching technique. The phase formation was confirmed by XRD. The thin films were prepared by the conventional flash evaporation technique to ensure stoichiometry and to avoid dissociation. The XRD, TEM and RBS studies were done for structural and compositional characterization of thin films. The results show that our method of preparation of bulk as well as thin films leads to no change in stoichiometry. The thicknesses of thin films as measured by the in-situ quartz crystal monitor and those evaluated from the RBS spectra agree well. The thermoelectric power measurements on thin films were made by the integral method and the data analyzed by the Jain-Verma theory to evaluate the power index in the energy dependent relaxation time, giving an idea about the nature of scattering. The detection of nature of scattering in the thin film material will help us to optimize the figure of merit and hence to enhance the thermoelectric properties. © 2003 IEEE.

V. Damodara Das

Bismuth

Bismuth alloys

Characterization

Scattering parameters

Semiconductor materials

stoichiometry

Thermal conductivity

Thermoelectricity

Thin films

Tin alloys

Transistors

X ray scattering

COMPOSITIONAL CHARACTERIZATION

CONDUCTING MATERIALS

Equations

FLASH EVAPORATION TECHNIQUE

MELT QUENCHING TECHNIQUES

QUARTZ CRYSTAL MONITORS

Thermoelectric application

Thermoelectric properties

Film preparation

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Growth of thermoelectric Bi/sub 85/Sb/sub 15/ alloy thin films and their characterization by XRD, TEM & RBS

International Conference on Thermoelectrics, ICT, Proceedings

The Jain-Verma theory has been applied to the thermoelectric data of vacuum flash-evaporated and annealed polycrystalline thin films of (Bi0.5Sb0.5)2Te3 alloys of different thicknesses to study the nature of principal carrier scattering mechanism and also to know the extent of other scattering mechanisms, simultaneously. It is found that the value of the energy dependent scattering index parameter lies between -0.45 and -0.4. This indicates that, even though the principal scattering mechanism in the films is the normal lattice scattering, other scattering like 'impurity' scattering, surface scattering and grain boundary scattering may be present. © 2001 Elsevier Science Ltd. All rights reserved.

Solid State Communications

Thermoelectric behaviour of (Bi0.5Sb0.5)2Te3 semiconducting alloy thin films

Antimony thin films of different thicknesses have been vacuum-deposited onto cleaned glass substrates held at room temperature, and their thermoelectric power and electrical resistivity have been evaluated as functions of temperature and thickness. The Jain-Verma theory of the size effect on the thermoelectric power of thin films has been applied to the experimental data to understand the nature of the scattering mechanism in antimony thin films. The carrier mean free path Ig and the Seeback coefficient Sg of the bulk (with thin film microstructure) have been evaluated at room temperature from the resistivity-thickness and thermoelectric power-thickness plots, respectively, as 1200 Å and 30.1 μVK-1. Using these values Sf/Sg, the thermoelectric power of the films (in the units of Sg, as given by the Jain-Verma theory has been plotted as a function of thickness t/Ig (in units of Ig) for different values of the scattering parameter b to generate a family of curves. By finding out on what curve or curves the experimental thermoelectric power values lie, the scattering parameter has been evaluated to be -0.2, so that the relaxation time τ varies as τ=a E-0.2 in antimony thin films. It is inferred from this that the major scattering process in our antimony thin films is lattice scattering even though other scattering processes also occur to a lesser extent in the films in the temperature range studied. © 1990.

Vacuum

Nature of principal scattering mechanism in well-annealed antimony thin films-analysis from thermoelectric data

Thin antimony films of thicknesses in the range 30 to 200 nm have been vacuum deposited on glass substrates at room temperature. After annealing for about an hour at 500 K, the thermoelectric power and electrical resistivity were measured in vacuum as a function of temperature. The thermoelectric power and electrical conductivity data were combined and simultaneously analysed using the effective mean free path theory of size effect in thin films developed by Tellier and Pichard et al. In addition, their temperature dependence was also analysed. It was found that the thermoelectric power is positive and increases with increasing temperature and is inversely proportional to the thickness of the film. The electrical resistivity was found to be temperature dependent with the temperature coefficient of resistivity being positive, and inversely proportional to the thickness of the film. Analysis combining the data from the thermoelectric power and electrical conductivity measurements has led to the determination of mean free path, carrier concentration, effective mass, Fermi energy and the parameter {Mathematical expression} The data were analysed for least squares fitting by local functions, such as the spline functions, which eliminates possible errors in conventional least squares fitting of data using non-local functions valid throughout the range. © 1989 Chapman and Hall Ltd.

Journal of Materials Science

Size and temperature dependence of thermoelectric power and electrical resistivity of vacuum-deposited antimony thin films

Anthropology News

Association for Africanist Anthropology

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Status of ion microbeam facility at the Institute of Physics, Bhubaneswar, India

Growth of thermoelectric Bi85Sb15 alloy thin films and their characterization by XRD, TEM &amp; RBS

Journal	Data powered by TypesetInternational Conference on Thermoelectrics, ICT, Proceedings
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
Open Access	No