Light Scattering from Hydrogenated Microcrystalline Silicon Deposited on Glass-Substrates after cw CO2-Laser Irradiation

27th European Photovoltaic Solar Energy Conference and Exhibition; 2615-2619
A detailed Raman spectroscopic study of the amorphous-to-microcrystalline phase transition in a-Si:H films on glass substrates is presented. In order to induce crystallization of the films a continuous wave CO2-laser working at 10.6 μm was utilized at constant irradiation time/variable power density and at constant power density /variable irradiation time. The analysis of the Raman spectra made it possible to follow quantitatively the induced crystallization. The crystallite size distribution and the film stress are estimated directly from spectroscopic data after a fitting procedure of the experimental data. The Raman line shapes are evaluated in view of the effect of the finite nanocrystal size on the phonons by investigating the CO2-laser induced shift of the c-Si peak. The results are discussed in the context of recent experimental and theoretical works concerning the bond polarizability.