7 research outputs found
Low Cost Solar Array Project: Composition Measurements by Analytical Photon Catalysis
The applicability of the photon catalysis technique for effecting composition analysis of silicon samples was assessed. Third quarter activities were devoted to the study of impurities in silicon matrices. The evaporation process was shown to be congruent; thus, the spectral analysis of the vapor yields the composition of the bulk sample. Qualitative analysis of metal impurities in silicon was demonstrated e part per million level. Only one atomic spectral interference was noted; however, it is imperative to maintain a leak tight system due to chemical and spectral interferences caused by the presence of even minute amounts of oxygen in the active nitrogen afterglow
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Low cost solar array project composition measurements by analytical photon catalysis. Final report, October 1, 1978-September 30, 1979
The object of this research is to assess the applicability of the photon catalysis technique for effecting composition analysis of silicon samples. In particular, the technique is to be evaluated as a detector for the impurities Al, Cr, Fe, Mn, Ti, V, Mo and Zr. During the first year Al, Cr, Fe, Mn, Ti and Si have been detected with the photon catalysis method. The best fluorescence lines to monitor were established, and initial sensitivites to each of these elements were established by atomic absorption calibration. In the course of these tests vapor pressure curves for these six pure substances have also been mapped. The detection of these impurities in silicon matrices were studied. The evaporation process was shown to be congruent; thus, spectral analysis of the vapor will yield the composition of the bulk sample. Qualitative analysis of metal impurities in silicon was demonstrated below the part per million level. A parametric study for the purpose of establishing optimal running conditions was completed. The parameters varied were temperature, nitrogen and argon pressures, pumping speed, and microwave power. In addition to these mainline tasks much ancillary information was obtained. The emission signatures were determined for several additional elements including As, Bi, B, Ca, Cu, Cr, Ga, Ge Mg, Na, P and Pb. Ionic emission lines for Ca and Mg were determined to be useful for analysis.Many metal hydrides and alkyls were found to be detectable by the active nitrogen technique. As a result of these studies it is concluded that the photon catalysis technique is suitable for bulk analysis of solar grade silicon. (WHK