Study of bulk photovoltaic effect and photovoltaic barrier effect distributions in multicrysta lline silicon

Abstract

Photoelectric voltage distribution on mc-Si wafers subjected to phosphorus gettering processes was investigated. It was demonstrated, that the measured photoelectric voltage results from bulk photovoltaic effect and photoelectric voltage connected with potential barriers occurring on grains boundaries. It was shown that sample illumination results in reduction of bulk photoelectric effect enabling better visualization and investigation of potential barriers. Relations determining photoelectric voltage distribution on single barrier are given.1 Introduction Today the dominance of solar cells production by crystalline silicon with multicrystal (mc-Si) growing faster then monocrystal is observed. In order to obtain better electric parameters of mcSi, various techniques are applied for monitoring resisitivity distribution, potential barrier height distribution and especially the value and distribution of charge carrier lifetime in this material. The lifetime measurements are needed for initial material evaluation and for assessment of the influence of technological processes on gettering and passivation of extended defects, gliding plane and grain boundaries. In this research mc-Si used for solar cells production was investigated. Nonhomogeneous resistivity distributions were studied by measurements of the bulk photovoltaic effect (BPV) For revealing the space distribution of potential barriers and for evaluation their height, measurements of photovoltaic effect with illumination were carried on.