Properties of electrodeposited semiconductor thin films are dependent upon the electrolyte composition, plating time, and temperature as well as the current density and the nature of the substrate. In this study, the influence of the electrodeposition parameters such as deposition voltage, deposition time, composition of solution, and deposition temperature upon the properties of In2S3films was analyzed by the Taguchi Method. According to Taguchi analysis, the interaction between deposition voltage and deposition time was significant. Deposition voltage had the largest impact upon the stoichiometry of In2S3films and deposition temperature had the least impact. The stoichiometric ratios between sulfur and indium (S/In: 3/2) obtained from experiments performed with optimized electrodeposition parameters were in agreement with predicted values from the Taguchi Method. The experiments were carried out according to Taguchi orthogonal array L27(3^4) design of experiments (DOE). Approximately 600 nm thick In2S3films were electrodeposited from an organic bath (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3·5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). An X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDS) unit, and scanning electron microscope (SEM) were, respectively, used to analyze the phases, elemental composition, and morphology of the electrodeposited In2S3films.

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Within the last few years, there has been notable progress in understanding the growth mechanisms of semiconductor thin films for photovoltaic (PV) applications. Electrodeposition continues to be a complex deposition technique that can lead to regions of low quality (for example, cracks) in films. Such cracks can form porous zones on the substrate and diminish the heterojunction interface quality of a PV cell. In this paper, electrodeposition of In 2 S 3 films was systematically and quantitatively investigated by varying electrodeposition parameters including bath composition, current density, deposition time, and deposition temperature. Their effects upon the morphology, composition, and film growth mechanism were studied with the help of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and digital imaging analysis (using fracture and buckling analysis software). In addition, the effect of different annealing treatments (200 • C, 300 • C, and 400 • C in air) and coated glass-substrates (Mo, ITO, and FTO) upon the properties of the In 2 S 3 films was analyzed. Furthermore, the Taguchi/Design of Experiments (DOE) Method was used to determine the optimal electrodeposition parameters in order to improve the properties. Indium (III) sulfide (In 2 S 3 ) is a promising semiconductor material (III-VI compound), suited for many technological applications like optoelectronic, 1 photovoltaic, 2 and photoelectric devices 3 due to its stability, large energy bandgap (∼2.3 eV), and photoconductive behavior. 4 β-In 2 S 3 is an n-type semiconductor material that has been considered as a non-toxic substitute for cadmium-containing PV cells. 5 It has potential to replace cadmium sulfide (CdS) as a buffer layer in copper indium gallium selenide/sulfide (CIGS)-based PV cells due to environmental concerns. 6 Several reports have been published on synthesis of In 2 S 3 films by numerous deposition techniques. These films have exhibited diverse morphologies and structural properties. 7-11 In In 2 S 3 (from atomic layer deposition)-based CIGS PV cells, an efficiency of 16.4% 12 has been achieved, which is few percent less than the 20.8% efficiency reported for CdS-based CIGS PV cells with the CdS deposited by chemical bath deposition (CBD). 13 Electrodeposition is considered an economical and time-saving alternative to vacuum-based techniques for depositing semiconductor thin films onto a substrate with full coverage and high growth yield. 14 It offers high material utilization efficiency, precise control with proper bath chemistry, and in-situ monitoring. 14,15 In 2011, electrodeposited In 2 S 3 -based CIGSe PV cells yielded an energy conversion efficiency of 10.2%. 16 However, electrodeposition still remains a complex technique for synthesizing thin films due to several deposition parameters, which can affect the properties of the films. 17,18 Poor adhesion, nonuniformity, flaking, and cracking 19 of films are common problems when electrodepositing films onto smooth surfaces, 14 as nucleation and growth...

No abstract

Within the last few years, there has been notable progress in understanding the growth mechanisms of semiconductor thin films for photovoltaic (PV) applications. Electrodeposition continues to be a complex deposition technique that can lead to regions of low quality (for example, cracks) in films. Such cracks can form porous zones on the substrate and diminish the heterojunction interface quality of a PV cell. In this paper, electrodeposition of In 2 S 3 films was systematically and quantitatively investigated by varying electrodeposition parameters including bath composition, current density, deposition time, and deposition temperature. Their effects upon the morphology, composition, and film growth mechanism were studied with the help of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and digital imaging analysis (using fracture and buckling analysis software). In addition, the effect of different annealing treatments (200 • C, 300 • C, and 400 • C in air) and coated glass-substrates (Mo, ITO, and FTO) upon the properties of the In 2 S 3 films was analyzed. Furthermore, the Taguchi/Design of Experiments (DOE) Method was used to determine the optimal electrodeposition parameters in order to improve the properties.