V.Mary Pradeepa Journal of Engineering Research and Application www.ijera.com ISSN: 2248-9622 Vol. 10, Issue 01 (Series -II) January 2020, pp20-24 www.ijera.com DOI: 10.9790/9622-100102202420|P a g e Synthesis and Characterizations of Cadmium Sulphide (CdS) Thin Films by Chemical Spray Deposition Technique V.Mary Pradeepa*,K.Kesavan**, (Periyar Maniammai Institute of Science & Technology,Deemed to be University, Vallam, Thanjavur. (Periyar Maniammai Institute of Science &Technology,Deemed to be University, Vallam, Thanjavur. Corresponding Author: kk7blr@gmail.com ABSTRACT: Cadmium Sulphide is an n-type semiconductor and it is perfectly suitable for a window layer in thin films based solar cells due to its desirable structural and optical properties. CdS thin films have been coated on microscopic glasssubstrate around 300⁰ C by spray pyrolysis technique. Cadmium acetate and Thiourea in different concentrations were used as precursors. The fabricated films are characterized for various properties. Their structural properties were studied by X-ray diffraction,morphological properties are studied by SEM with EDX, and optical studies determined by UV-VIS spectrometry. The band gap value of the CdS thin films varied from 2.1eV to 2.4eV. Keywords: CdS, Spray pyrolysis, XRD, SEM-EDX , UV-VIS, Band gap. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 15-01-2020 Date of Acceptance: 31-01-2020 -------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION The semiconducting materials attract a considerable attention due to their electrical and optical properties. Cadmium sulphides(CdS) have been widely studied for extensive optoelectronic applications including: solar cells, smart windows, light emitting diodes, optical communications, flat panel displays[1], photo-transistors[2]. CdS is II-VI semiconductors have n- type semiconducting properties with an electrical resistivity of 10 -2 -10 -4 cm and a band gap is 2.42eV [3]at room temperature.Cadmium sulphides have been considered as one of the promising material for solar cell application due to its low resistivity and high electrical conductivity and high transmittance in the visible range of solar spectrum [4]. CdS thin films have been synthesized using various physical and chemical deposition techniques including: chemical bath deposition(CBD)[5], activated reactive evaporation, spray pyrolysis[6], rf-sputtering, dc- sputtering[7],chemicalvapour deposition[8],reactive magnetron sputtering, metal oxide chemical vapour deposition (MOCVD)[9], pulsed laser deposition (PLD) and sol gel. Spray pyrolysis is one of the thin film deposition techniques that has produced considerably large area and uniform films in variety of different materials and provides economical and efficient usage of evaporent[10]. The aim of this study is to carry out experimental studies of the structural, optical and morphological properties of the film of cadmium sulphides deposited by spray pyrolysis technique.The film properties depend on the precursor preparation, spray rate, the substrate temperatureand the cooling and flowrate. II. EXPERIMENTAL DETAILS: Preparation of thin films For the thin film preparation, different precursor concentrations0.05M,0.1M,0.15M,and 0.2M of cadmium acetateCd(CH 3 COO) 2 with 0.1M concentration of thioureaCS(NH 2 ) 2 were dissolved in distilled water. The slides were washed in a detergent solution rinsed with de-ionised water and cleaned with acetone then dried in air for clean glass substrate. The nozzle to substrate distance was 30cm and the flow rate of the solution was 3ml/min. The substrate temperature was maintained at 300⁰ C.When compressed air with the precursor solution was passed through the nozzle at constant pressure,the film was deposited on the heated substrate (300⁰ C)for producing CdS thin films.Optical absorption and transmission data were obtained with an UV-VIS spectrometer in the range of 300nm-900nm.The crystalline structure of the thin films was analysed using X-ray diffractometre with CuK radiation of 1.5418 ⁰ .Scanning electron microscopes and Energy dispersive X-ray analysis are used to study the surface morphology and true composition of the sample being analysed and percentage of materials involved in the CdS thin films. RESEARCH ARTICLE OPEN ACCESS