Nanoscale Characterization of Microcrystalline Silicon Solar Cells by Scanning Near-Field Optical Microscopy

Abstract

The photovoltaic mapping technique of solar cells has been developed and tested on hydrogenated microcrystalline silicon (µc-Si:H) solar cells by scanning near-field optical microscopy (SNOM). Near-field light through a fiber probe illuminates the Si layer of a solar cell and then the photovoltaic effect appears locally. Topographic and photovoltaic images were obtained using a scanning probe and defective domains with diameters of 100–200 nm appeared in the photovoltaic images. A similar inhomogeneity was observed by conductive atomic force microscopy. The photovoltaic images demonstrate that film inhomogeneities affect solar cell performance. The results indicate that a scanning near-field microscope is useful for the quality monitoring of nanoscale junctions of hydrogenated microcrystalline silicon solar cells.