Measurements of effective optical reflectivity using a conventional flatbed scanner—Fast assessment of optical layer properties

A conventional flatbed scanner equipped with an additional diffusor is used for rapid measurements of an important figure of merit for optical surfaces, the effective reflectivity of devices such as solar cells. The application of the technique to multicrystalline silicon wafers with light-trapping structures obtained by electrochemical etching is shown. The use of this method for rapid quality control in production environments as well as in the lab is envisaged: even with a non-optimized diffusor, a spatial resolution of 0.1×0.1 mm² can be achieved, with an accuracy of the reflectivity measurements of 1% and data-acquisition times around 10 s per wafer.