MARC 主機 00000nam  2200349   4500 
001    AAI3052672 
005    20070813114357.5 
008    070813s2002                        eng d 
020    9780493673714 
035    (UMI)AAI3052672 
040    UMI|cUMI 
100 1  Tarasov, Igor 
245 10 Defect diagnostics using scanning photoluminescence in 
       multicrystalline silicon for solar cells 
300    107 p 
500    Source: Dissertation Abstracts International, Volume: 63-
       05, Section: B, page: 2518 
500    Major Professors:  Christos S. Ferekides; Sergei Ostapenko
502    Thesis (Ph.D.)--University of South Florida, 2002 
520    The main goal of the project is to develop a scanning room
       temperature photoluminescence (PL) mapping system (both 
       hardware and software) and to apply this technique to 
       characterize areas with high and low recombination 
       activity of defects in multicrystalline silicon (mc-Si) 
       wafers for solar cells. The objectives are (1) to analyze 
       the recombination activity of dislocations in as-grown and
       processed mc-Si wafers, (2) to find a correlation between 
       topology of PL distribution and distributions of minority 
       carrier lifetime, dislocations, and residual elastic 
       stress in full-size mc-Si wafers and solar cells, and (3) 
       develop the algorithm of electronic quality control in 
       silicon wafers using scanning PL spectroscopy 
520    A positive correlation between the band-to-band PL 
       intensity and the distribution of minority carrier 
       lifetime was found in me-Si produced by Edge-Defined Film-
       Fed Growth and Block Cast techniques. In the regions with 
       enhanced recombination activity of defects (low minority 
       carrier lifetime) a new "defect" luminescent band with a 
       maximum at 0.78eV was observed. The intensity of this 
       defect band is negligible in wafer regions with low 
       recombination activity. Its distribution measured across 
       the entire mc-Si wafer shows a reverse contrast to the 
       band-to-band PL intensity. The concentration of the 0.78eV
       defect centers shows only a small reduction between the as
       -grown wafer and final solar cell, contrary to a strong 
       increase of the lifetime due to gettering and passivation 
       mechanisms. Low-temperature PL spectroscopy gave clear 
       evidence that the defect luminescence has a dislocation 
       origin. This was confirmed by dislocation mapping. The 
       defect PL band has a strong linear polarization up to &
       sim;60% due to the elastic stress field, in contrast to a 
       low polarization degree for the band-to-band luminescence.
       The internal stress mapping was performed in this project 
       using scanning infrared polariscopy. The defect centers 
       are localized in the vicinity of a high residual stress, 
       which may account for a stress-induced polarization of the
       defect band. Scanning PL spectroscopy can be applied for 
       monitoring of dislocation activity in commercial mc-Si 
       wafers and solar cells 
590    School code: 0206 
590    DDC 
650  4 Engineering, Electronics and Electrical 
650  4 Energy 
690    0544 
690    0791 
710 20 University of South Florida 
773 0  |tDissertation Abstracts International|g63-05B 
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