Growth of semiconducting (CdS, CdSe and ZnSe) and conducting films (NiFe) and investigation on their electrical, magnetic and optical properties

ABSTRACT GROWTH OF SEMICONDUCTING (CdS, CdSe and ZnSe) AND CONDUCTING FILMS (NiFe) AND INVESTIGATION ON THEIR ELECTRICAL, MAGNETIC AND OPTICAL PROPERTIES BEDİR, Metin Ph.D. in E.P., University of Gaziantep Supervisor: Prof.Dr. Ömer Faruk BAKKALO?LU Co-supervisor: AssistProf.Dr. Mustafa ÖZTAŞ November 2002, 166 Pages In this study, semiconducting CdS, CdSe and ZnSe thin films were developed by using spraying pyrolysis and electrodeposition method, conducting NiFe alloy films were grown by electrodeposition method on different substrates under different deposition conditions and their electrical, magnetic and optical properties were widely investigated by using different techniques. The optical properties of the semiconducting were investigated from optical absorption coefficient and transmittance spectra data using double beam visible spectrofotometer. By using these data the band gap energies of the semiconductingthin films were determined. The crystal structures of semiconducting (CdS, CdSe, and ZnSe) thin films and conducting (NiFe) films were determined from x-ray diffraction peaks and the thicknesses of the sprayed CdS, CdSe and ZnSe thin film samples were calculated by using weighing method. The electrical properties of the semiconducting thin film samples were investigated by Van der Pauw method ( four ohmic contact). The changes in the resistivities, conductivities and Hall mobilities of the semiconducting thin films under different substrate temperatures have been investigated. The surface morphology of NiFe alloy film samples were examined from scanning electron microscope (SEM) photos nickel ( Ni) and iron (Fe) concentration in NiFe alloy film samples were calculated by using the atomic absorption spectrometer results also the thicknesses of samples were determined. The electrical and magnetic properties of electrodeposited NiFe conducting alloy films were investigated by using a 2 Tesla home made electromagnet and Van der Pauw method ( four ohmic contact), respectively, for different geometries ( magnetic fields were applied under the different angles onto film surface ) at room temperature. The temperature dependent magnetoresistance measurements were done under the influence of a constant magnetic field of 0.8 Tesla for two different geometries ( longitutional and transverse ). Magnetization properties of the NiFe alloy film samples were also determined by vibrating sample magnetometers (VSM). Key words: Spray Pyrolysis method, Electrodeposition method, CdS, CdSe, ZnSe, magnetoresistance, NiFe alloy films.