Simulation and analysis of photovoltaic cells require both optical modelling and semiconductor device modelling. Often, both are very involved and therefore, the simulations or analyses of the photovoltaic cells make compromises in either modelling.
Here, we present a simple coupled model, where the optical modelling is done using finite difference beam propagation method and the electronic modelling is done using the drift-diffusion model. Starting from the semi-classical Boltzman transport equation, we make valid approximations to arrive at the drift-diffusion equation which is further discretized by the Scharfetter-Gummel Scheme. For optical modelling, we start with Maxwell`s equations, apply successive valid approximations and arrive at the finite- difference beam propagation method. We then solve both the equations simultaneously, the input flux at every step used for calculation of carrier transport in the drift diffusion equation is supplied by the solution of the optical beam propagation. This coupled model would give us a fast and simple method to simulate and analyze novel optical structures for photovoltaic cells.
Initial results of both the independent models are very encouraging. Equilibrium and non-equilibrium transport properties have been successfully described by the electronic modelling, similarly for low contrast photonic structures, FD-BPM is a long-proven method. We would present an integrated approach to arrive at a very fast, simple yet efficient model for simulation of optical structures for photovoltaic applications.