Analysis of Device Performance by Quasi Three-Dimensional Simulation for Thin Film Polycrystalline Silicon Solar Cells with Columnar Structure

Abstract

In order to realize high efficiency thin film polycrystalline silicon (poly-Si) solar cells, a novel method of quasi three-dimensional simulation using a cylindrical coordinate system was proposed. Optimum design of cell configuration and analysis of device performance have been demonstrated. In this simulation we used realistic physical values for parameters, such as interface recombination velocity at grain boundaries and diffusion length of minority carriers. Interface recombination velocity at grain boundaries (which has a strong effect on cell performance) should be less than 103 cm/s to obtain high cell performance. Even at a relatively short diffusion length of 50 µm, high efficiency of more than 16–18% can be expected at a film thickness of 5–20 µm when grain size is 10 µm, which is appropriate for the utilization of solar grade Si of reasonable material quality.