Preparation and characterization Of Cu2s thin films for possible applications

Abstract

newline newlineThis thesis presents the results of investigation of vacuum newlineevaporated Cu2S film and the process involved during deposition Cu 2S is an newlineinteresting semiconductor material with electrical optical and physical newlineproperties varying significantly as a function of composition It is a suitable newlinematerial to be used in solar cell because it has very high absorption coefficient newlinefor wavelength constituting the solar spectrum Semiconducting copper newlinesulphide Cu6S thin films were deposited on glass substrates at room newlinetemperature by vacuum evaporation method with four different thicknesses newlineFilms were deposited under a pressure of 10 6 Torr at an evaporation rate of newline3Å sec Rotary drive was employed to obtain uniformity in film thickness newlineThicknesses of the film were measured by using quartz crystal monitor newlineCharacterization of the film has been carried out using Xray diffraction newlineXRD and Raman spectroscopy The two point probe method was used for newlinethe investigation of electrical properties and four point probe was used for newlineresistivity analysis Hall effects measurements were carried out to determine newlinethe size dependent electrical properties of the film newlineXray diffraction studies show that lower thickness films are a newlinemixture of amorphous and polycrystalline while higher thickness films bear newlinepolycrystalline nature It was also observed that at lower thickness the formed newlinefilm is a mixture of either or both phases of chalcosite Cu2S and covellite newlineCuS whereas higher thickness Cu2S film changes its crystal structure from newlineCu2S to CuS and exhibit deviation in the composition of the film Raman newlinespectroscopy was used as a rapid identification of the composition of the film newlineRaman shifts at 472 cm and 474 cm indicates that the films deposited at newlinelower thickness were chemically close to CuS copper rich phase while newlinehigher thickness films were CuS sulphurrich phase This change in the newlinecomposition of the film at higher thickness meant that the films were newlinedeposited as layers with those layers next to substrate having a composition newlinewith a higher CuS