Enhancement of the optical absorption of thin-film of amorphorized silicon for photovoltaic energy conversion

In this study we report for the first time a method for simple, precise and single-step generation of thin film of amorphous silicon (a-Si) on silicon substrate induced by laser pulses with the frequency of megahertz under ambient conditions for solar cell fabrication. Also, the effect of laser parameters such as pulse width is investigated by developing an analytical model for the calculation of the non-dimensional surface temperature with various pulse widths; it was found from experimental and analytical results that for a constant power and repetition rate, an increase in the pulse duration corresponds to a significant increase in the surface temperature which results in an increase in the amount of amorphorized material as well as improvement of light absorption. A Scanning Electron Microscope (SEM), scanning near-field optical microscope (SNOM), a Micro-Raman, Energy Dispersive X-ray (EDX) spectroscopy and an optical spectrometer were used to analyze the optical and material properties of the amorphorized thin layer on Si-substrate. 2011 Elsevier Ltd. All rights reserved