Analyzing UV/Vis/NIR Spectra—Correct and Efficient Parameter Extraction

Correct and efficient optical analyses of transparent conducting oxide (TCO) and absorbing layers are necessary to select appropriate materials for thin-film solar cells. A non-numerical theoretical concept has been developed to extract approximation-free optical parameters from UV/Vis/NIR spectra for single-layer systems. Complex parameter evaluation is possible. Approximations for multilayer systems and measurements without integrating spheres are provided. UV/Vis/NIR spectroscopy measurements (Perkin Elmer Lambda 750) were made, evaluated, and discussed for semiconducting n-doped silicon (Active Business Company GmbH), insulating boron silicate glass (BSG, AF45 from Schott AG) and a TCO thin film, namely, aluminum-doped zinc-oxide (ZnO:Al), upon BSG. A variety of results, including conductivities, were compared (relative) to those of the well known Swanepoel model (which neglects reflection spectra). Quantum mechanical potential barrier models were applied to reevaluate spectra in order to compare it (absolute) with measured data.