High spatial resolution characterization of silicon solar cells using thermoreflectance imaging

Thermoreflectance imaging is shown to be a high resolution, non-contact method of quantitatively characterizing device performance and identifying electrical shunts in conventional multicrystalline silicon solar cells. Results are in quantitative agreement with a commercial lock-in infrared thermography system but offer an order of magnitude improvement in spatial resolution. Highly resolved thermoreflectance imaging enables extraction of quantitative, spatially resolved device performance characteristics, including local IV curves and local diode ideality factors, offering detailed physical characterization of performance-limiting defects that cannot be obtained from conventional bulk cell testing. Finally, thermoreflectance maps of heat spreading from a point defect provide a simple means of quantifying thermal parameters such as thermal diffusivity and thermal conductivity, which are key field performance indicators. (C) 2011 American Institute of Physics. [doi:10.1063/1.3629979]