Jayakrishnan, R; Dr.Vijayakumar, K P(Cochin University of Science & Technology, April , 2008)
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Abstract:
The present thesis can be divided into three areas:1) the
fabrication of a low temperature photo-luminescence and photoconductivity
measuring unit 2) photo-luminescence in the chalcopyrite
CulnSez and CulnS2 system for defect and composition analysis and
3) photo-luminescence and photo-conductivity of In:JS3. This thesis
shows that photo-luminescence is one of most essential semiconductor
characterization tool for a scientific group working on photovoltaics.
Tools which can be robust, non-destructive, requiring minimal sample
preparation for analysis and most informative of the device
applications are sought after by industries and this thesis is towards
establishing photo-luminescence as "THE" tool for semiconductor
characterization. The possible application of photo-luminescence as a
tool for compositional and quality analysis of semiconductor thin
films has been worked upon by this thesis. Photo-conductivity
complement photo-luminescence and together they provide all the
information required for the fabrication of an opto-electronic device.
Description:
Department of Physics,
Cochin University of Science and Technology
Anita, Warrier R; Dr.Vijayakumar, K P(Cochin University of Science & Technology, August , 2010)
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Abstract:
Non-destructive testing (NDT) is the use of non-invasive techniques to determine the
integrity of a material, component, or structure. Engineers and scientists use NDT in a
variety of applications, including medical imaging, materials analysis, and process control.Photothermal beam deflection technique is one of the most promising NDT technologies.
Tremendous R&D effort has been made for improving the efficiency and simplicity of this
technique. It is a popular technique because it can probe surfaces irrespective of the size of
the sample and its surroundings. This technique has been used to characterize several
semiconductor materials, because of its non-destructive and non-contact evaluation
strategy. Its application further extends to analysis of wide variety of materials. Instrumentation of a NDT technique is very crucial for any material analysis. Chapter two
explores the various excitation sources, source modulation techniques, detection and signal
processing schemes currently practised. The features of the experimental arrangement
including the steps for alignment, automation, data acquisition and data analysis are
explained giving due importance to details.Theoretical studies form the backbone of photothermal techniques. The outcome of a
theoretical work is the foundation of an application.The reliability of the
theoretical model developed and used is proven from the studies done on crystalline.The technique is applied for analysis of transport properties such as thermal diffusivity,
mobility, surface recombination velocity and minority carrier life time of the material and
thermal imaging of solar cell absorber layer materials like CuInS2, CuInSe2 and SnS thin
films.analysis of In2S3 thin films, which are used as buffer layer material in
solar cells. The various influences of film composition, chlorine and silver incorporation in
this material is brought out from the measurement of transport properties and analysis of
sub band gap levels.The application of photothermal deflection technique for characterization of solar cells is a
relatively new area that requires considerable attention.The application of photothermal deflection technique for characterization of solar cells is a
relatively new area that requires considerable attention. Chapter six thus elucidates the
theoretical aspects of application of photothermal techniques for solar cell analysis. The
experimental design and method for determination of solar cell efficiency, optimum load
resistance and series resistance with results from the analysis of CuInS2/In2S3 based solar
cell forms the skeleton of this chapter.
Description:
Department of Physics,
Cochin University of Science and Technology