Sanal, K C; Dr.Jayaraj, M K(Cochin University of Science And Technology, January 27, 2014)
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Abstract:
Semiconductor physics has developed significantly in the field of re-
search and industry in the past few decades due to it’s numerous
practical applications. One of the relevant fields of current interest in
material science is the fundamental aspects and applications of semi-
conducting transparent thin films. Transparent conductors show the
properties of transparency and conductivity simultaneously. As far
as the band structure is concerned, the combination of the these two
properties in the same material is contradictory. Generally a trans-
parent material is an insulator having completely filled valence and
empty conduction bands. Metallic conductivity come out when the
Fermi level lies within a band with a large density of states to provide
high carrier concentration. Effective transparent conductors must nec-
essarily represent a compromise between a better transmission within the visible spectral range and a controlled but useful electrical con-
ductivity [1–6]. Generally oxides like In2O3, SnO2, ZnO, CdO etc,
show such a combination. These materials without any doping are
insulators with optical band gap of about 3 eV. To become a trans-
parent conductor, these materials must be degenerately doped to lift
the Fermi level up into the conduction band. Degenerate doping pro-
vides high mobility of extra carriers and low optical absorption. The
increase in conductivity involves an increase in either carrier concen-
tration or mobility. Increase in carrier concentration will enhance the
absorption in the visible region while increase in mobility has no re-
verse effect on optical properties. Therefore the focus of research for
new transparent conducting oxide (TCO) materials is on developing
materials with higher carrier mobilities.
Description:
Department of Physics
Cochin University of Science and Technology
Pradeep,B; Dr.Joy, George(Cochin University of Science And Technology, November , 1986)
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Abstract:
This thesis deals with the preparation and properties of two compounds of V-II family, viz.
bismuth telluride and bismuth oxide, in thin filmform. In the first chapter is given the resume of
basic solid state physics relevant to the work reported here. In the second chapter the different
methods of thin film preparationtia described. Third chapter deals with the experimental techniques used for preparation and characterization of the films. Fourth chapter deals with the preparation and propertiesof bismuth telluride films. In next four chapters, the preparation and properties of bismuth oxide films are discussed in detail. In the last chapter the use of Bi205 films in the fabrication of Heat mirrors is examined and discussed.
Description:
Department of physics, Cochin University of Science And Technology