Near-field scanning optical microscopy studies of Cu(In,Ga)Se2 solar cells

Abstract
A near-field scanning optical microscope (NSOM) is used to study the local photoresponse of Cu(In,Ga)Se2 thin film solar cells. The grain boundaries of the small grains (10 μm). In addition, NSOM images show response variations from grain to grain and areas of reduced photoresponse which have no corresponding topography. Photovoltage imaging of the cleaved side of the solar cells reveals the depth and nonuniformities of the actual p-n junction. It is found that the response of the p-n junction varies on a 0.5 μm length scale.