tailieunhanh - Báo cáo hóa học: " Micro-spectroscopy on silicon wafers and solar cells"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Micro-spectroscopy on silicon wafers and solar cells | Gundel et al. Nanoscale Research Letters 2011 6 197 http content 6 1 197 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Micro-spectroscopy on silicon wafers and solar cells Paul Gundel Martin C Schubert Friedemann D Heinz Robert Woehl Jan Benick Johannes A Giesecke Dominik Suwito Wilhelm Warta Abstract Micro-Raman pRS and micro-photoluminescence spectroscopy pPLS are demonstrated as valuable characterization techniques for fundamental research on silicon as well as for technological issues in the photovoltaic production. We measure the quantitative carrier recombination lifetime and the doping density with submicron resolution by pPLS and pRS. pPLS utilizes the carrier diffusion from a point excitation source and pRS the hole density-dependent Fano resonances of the first order Raman peak. This is demonstrated on micro defects in multicrystalline silicon. In comparison with the stress measurement by pRS these measurements reveal the influence of stress on the recombination activity of metal precipitates. This can be attributed to the strong stress dependence of the carrier mobility piezoresistance of silicon. With the aim of evaluating technological process steps Fano resonances in pRS measurements are analyzed for the determination of the doping density and the carrier lifetime in selective emitters laser fired doping structures and back surface fields while pPLS can show the micron-sized damage induced by the respective processes. Introduction Silicon solar cells contribute by far the largest share to the world s photovoltaic facilities 1 . An important property to classify these silicon solar cells is the base material where two fundamentally different approaches can be observed in the photovoltaic industry multicrystalline and monocrystalline cells. While the fabrication of monocrystalline silicon is more expensive the efficiency potential of these cells is higher. The world record efficiency for .