Analysis of AlGaAs/GaAs solar cell structures by optical reflectance spectroscopy

The control of the thickness and composition of the GaAs cap and AlGaAs window layers is essential to the fabrication of high-efficiency AlGaAs/GaAs heteroface solar cells. The use of optical reflectance spectroscopy for the analysis of these structures is presented. The calculation of the reflectance of a system of thin films is described along with the computer program, REFIT, for the analysis of GaAs cell structures. Results are presented for structures at different stages in the solar cell fabrication process, and the method is applied to the analysis of the oxidation of high AlAs mole fraction AlGaAs layers.<
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