Use of seed layers for structure, optical, and electronic transport measurements on microcrystalline silicon on glass

A detailed structural analysis is provided by which the benefits of thin undoped 'seed layers' for the preparation of microcrystalline silicon on glass for material characterization are demonstrated. Raman spectroscopy and photothermal deflection spectroscopy (PDS) results reveal that 'seed layers' are not only effective for the growth of structurally homogenous films and for an extension of the range of deposition parameters in which highly crystalline material is grown, but also allow for preparing material on glass with properties very close to that of functional layers in thin film solar cells. Films which have successfully been tailored in this way are characterized with respect to electrical conductivity and optical absorption. Regarding conductivity, hydrogenated microcrystalline silicon material grown on a 'seed layer' exhibits a structure-dependent behaviour which is very similar to that observed for material grown on bare glass. Regarding optical absorption spectra, residual interference fringes, which indicate structural non-uniformities, can be successfully removed by means of 'seed layers'. As a result, more information is obtainable from PDS, and the data gained in this way are in good agreement with Raman spectroscopy results. Copyright (C) 2011 John Wiley & Sons, Ltd.