OPTICAL-ABSORPTION OF MICROCRYSTALLINE SI-NI THIN-FILMS

The optical absorption behavior of microcrystalline Si-Ni thin films ( mu c-Si-Ni) with a homogeneous and heterogeneous microstructure is inv estigated. In the homogeneous mu c-Si-Ni specimens the structural phas e consists of nanometer-sized grains. The heterogeneous specimens cons ist of a network of micrometer-sized crystalline Si needles. The meshe s of the Si needle network are filled with nanometer-sized grains. The ;optical absorption of the specimens is compared with the structural p roperties. The optical absorption of mu c-Si-Ni below an energy of 1.7 eV is described by a model of grain boundary states while above 2.0 e V optical transitions in the nanometer sized grains are discussed. (C) 1995 American Institute of Physics.