Investigations On Semiconducting Properties Of Silver Sulphide Thin Film Synthesized By Chemical Route

Abstract

Nanocrystalline properties of semiconducting compounds, particularly in thin film form are of great interest due to their wide technological and scientific application in detecting devices, solar cell, nanowire, nanotubes and energy convertors etc. Photoconductivity is one of the most important classes of electro-optical properties of materials such studies are used as a powerful tool in the understanding of solid state physics from bulk to nanocrystalline structures. Absorption properties are the important tool in the understanding of nature of band gap of the material. Photoluminescence Photoconductivity, Reflectance and Transmittance properties get very much affected by crystallite size. Structural studies are the important technique in the understanding of morphology, phase, crystal structure and chemical composition. Hence those studies can be and easy and reliable probe to estimate and calculated the different parameter regarding the bulk and nanocrystalline materials. newline In the light of growing importance of electro-optical properties both as scientific tool and as a basis of new devices the present thesis entitled Investigations on Semiconducting Properties of Silver Sulphide Thin Film Synthesized by Chemical Route is presented. The total work included in the thesis is divided into eight chapters. newlineThe first chapter presents the introduction of subject: newlineand#61656; Brief discussion of the thin film, nanocrystalline material, importance of silver sulphide material and the chemical bath deposition(CBD) technique. newlineand#61656; Aim and objective of present investigation. newlineand#61656; Significance of the study. newlineThe Second chapter embodies the Literature review of the present investigation. newlineThe Third chapter throws light on theory and mechanism of photoluminescence and photoconductivity newlineand#61656; Concept and theory involved in semiconducting compounds. newlineand#61656; Various theories used in understanding of photoconductivity and photoluminescence phenomena. newlineand#61656; Models and mechanisms involved in photoconductivity and photoluminescence factors influencing the phenomena. newlineThe Fourth chapter comprises of brief description on the experimental technique and various measuring instrument and required arrangement used in the present investigation. This chapter includes. newlineand#61656; Summary of the different technique used to prepare II-VI, III-V and I-VI semiconducting compound. newlineand#61656; Theory and mechanism of chemical bath deposition (CBD) method. newlineand#61656; Experimental arrangement and instrument used in different studies. newlineThe Fifth Chapter focus on the different optical studies of doped and undoped Ag2S and (Cd-Ag)S films. newlineand#61656; Results and discussion of nature of absorption edge. newlineand#61656; Tauc s plot and estimation of the band gap. newlineand#61656; Results and discussion of transmittance and reflectance curve. newlineand#61656; Photoluminescence spectral studies and discussion of its behavior and its dependence on crystallite size are also presented. newlineThe Sixth chapter deals with the photoconductivity studies of Ag2S and (Cd-Ag)S films it covers, newlineand#61656; The nature of dark current, photocurrent and the ratio Ipc/Idc with respect to change in composition. newlineand#61656; Lifetime, mobility and trap depths have been determined by analyzing the rise decay current. newlineThe Seventh chapter concentrates on the characterization studies of material prepared. It covers following studies, newlineand#61656; X-ray diffraction (XRD) studies and determination of particle size using Debye Scherer s formula is presented. newlineand#61656; Scanning electron microscopic (SEM) studies. newlineand#61656; Discussion on the observations of SEM and XRD studies. newlineand#61656; The Eight chapters include summary of the results and conclusion of the present investigation. newline newline