Modelling of Cu(In,Ga)Se2 Solar Materials/Devices

This paper will present the numerical modelling of CIGS materials/devices in order to better understand the physical properties of the device, having the goal to support/improve the fabrication technology based on an alternative hybrid sputtering/evaporation deposition.Optimization of the buffer-and absorption layer for high efficiency CIGS solar cells will be presented, since the band gap can be graded over a wide range by changing the Ga concentration in the thin film layer, which greatly affects the efficiency of the solar cell.The dependence of the solar cell properties on the thickness of the buffer layer and the effects of the bulk and interfaces defects on the solar cell parameters have been studied.The hybrid approach to modelling and simulation of thin film solar cells with a metal front grid on top of the transparent conductive oxide based electrode will be presented.A 3D model with high aspect ratio of device thickness (100s of nm) and its length and width (mm and cm range) was divided into two coupled models with different number of spatial dimensions (a 1D and a 3D model) on different length scales.The first one covers the modelling on the material stack level.The second model is coupled with the first and it takes into account the photovoltaic device's geometry.This approach enables the separation of the technology-dependent material simulation from the device shape and front grid design simulation.The metallization in the form of parallel fingers was investigated and optimized