International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2014): 5.611 Volume 5 Issue 2, February 2016 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Effect of Sputtered Zinc Oxide as Anti- Reflection Coating in Amorphous Silicon Solar Cell Dr. Satheesh Babu Gandla 1 , PhD, Nagesh M, M.Tech 2 Interdisciplinary Research Centre, R. V. College of Engineering, Bangalore, India Abstract: Amorphous Silicon (a:Si) solar cell structure is modelled and optimized using Lumerical FDTD solution & Lumerical Device. Sputtered Zinc Oxide (ZnO) transparent layer have been used on these Amorphous silicon solar cells as anti-reflecting coating (ARC). Simulation is done and optical properties and electrical characteristics have been investigated. It is found that the less Reflectance and more transmittance with application of Sputtered ZnO proved that it can be used as AR coatings. It is observed that after using sputtered ZnO as an ARC, conversion efficiency of solar cell is increased from its original 9.03% to 11.90 and it is also observed a thickness of 70-90 nm is optimum for use of the Sputtered ZnO as anti-reflection coatings. Keywords: Amorphous Silicon (a:Si), Sputtered ZnO, Anti Reflecting Coating(ARC), Conversion Efficiency 1. Introduction The performance of solar photovoltaic cells depends on its design, material properties, and fabrication technology. Numerical simulation is the best approach for solar cell researchers, which help to find out an optimized structure with good fitted parameters. As a result fabrication complexity, costs, and time reduce significantly. The major objectives of numerical modelling and simulation in solar cell research are testing validity of proposed physical structures, geometry on cell performance, and fitting of modelling output to experimental. Simulation of amorphous silicon solar cells helps in predicting the behaviour of amorphous solar cell devices. As the complexity in design of photovoltaic cells, it becomes more difficult to obtain analytic solutions for their performance. A combination of optical and electrical simulations which account for these non-ideal processes are necessary to accurately characterize the photovoltaic efficiency of the solar cell. For Optical Simulation FDTD Solutions is used, which is a high performance optical solver that can be used to simulate the interaction of light with a wide variety of solar cell designs. These designs can range from simple planar geometries to very complex patterning, and can include a wide variety of materials such as organics and metals. The result of the optical simulation is the spatial absorption in the substrate region, from which one can calculate the generation rate. This generation rate can be used in an electrical simulation in DEVICE to determine the responsivity and the photovoltaic efficiency of the solar cell. The CHARGE solver in DEVICE will account for the distribution of dopants that give rise to the built-in electric fields, the mobility of free carriers and the physical processes that result in the recombination of charge[11]. The function of solar cell is to obtain light generated carriers and these collection of light generated carriers generate current and power is dissipated in the load, 2. Methodology A. Modelling of a:Si solar Cell In this Section, the detail modelling of a:Si solar unit cell is given and defined different material structure which is used and also defined there geometry as shown in Fig.1. Sputtered ZnO is coated on Glass Substrate which acts Anti Reflecting Coating (ARC). For Simulation in FDTD solution, materials are defined in terms of refractive index and wavelength [12]. It also noted that the thickness of ZnO of 70nm to 90nm will be optimum to use it as ARC. The diffusion doping of N well (n++) is added with concentration of 1x1019 cm-3 and junction width is 0.4 µm and back diffusion(P++) is added with same concentration of 1x1019 cm-3 and Junction width is 0.2µm. Figure 1: Schematic of a a-Si single-junction solar cell B. Solar Cell Work flow The solar cell workflow starts with optical simulations in FDTD Solutions. Taking the solar spectrum into account, the solar generation rate is calculated from the optical absorption and used as a source in the subsequent electrical simulation in DEVICE to calculate the Conversion efficiency. C. Simulation Method Using Symmetry of the device, 2D simulation is performed, Using periodic nature of top electrodes, we focused on only one electrical period instead of the whole solar cell, smaller unit cell is chosen in FDTD and by simply repeating this unit Paper ID: NOV161162 1376