Solar LBIC scanning of high-efficiency point-contact silicon solar cells

The induced current response from a High Efficiency Concentrator (HECO) monocrystalline Si solar cell was mapped as a function of surface position and cell bias by using a solar light beam induced current (S-LBIC) mapping system while at the same time dynamically biasing the whole cell with an external voltage [1,2]. Recombination accounts for a major portion of the reduction in quantum efficiency in these cells [3.4]. This paper examines the spatial distribution of defect mechanisms causing a reduction of collected photocurrent of the backside point contact device structure [5] while under spot illumination. By examining the bias dependence of the S-LBIC maps, the identification of current loss mechanisms of solar cells under concentrated solar irradiance may be improved. The techniques employed to interpret the spatially distributed I-V curves are discussed and results presented. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.