PRELIMINARY STUDY OF THE EFFECT OF LITHIUM DIFFUSION ON THE PERFORMANCE OF SINGLE AND MULTICRYSTALLINE  p n  n+  SILICON SOLAR CELLS

A thesis submitted to the faculty of
San Francisco State University
in partial fulfillment of the
requirements for the
degree
 

Master of Science
in
Physics
 

by

Stephen M Beck

San Francisco, California

December 12, 1991

 

Multicrystalline and single crystal p+ n n+ silicon solar cells are diffused with lithium through their back surfaces.  Because of the relatively large diffusion coefficient of Li in Si, 47.5+/-6.42 µm/√hr, it diffuses through the entire 375 µm base in 2.0 - 3.7 hours.  It is expected that Li ions will reduce trapping at multicrystalline grain boundaries.  Preliminary results indicate overall cell maximum power less than non-Li diffused cells, however, cell maximum power does increase with depth of Li diffusion.