On the Effect of Impurities on the Photovoltaic Behavior of Solar Grade Silicon: II . Influence of Titanium, Vanadium, Chromium, Iron, and Zirconium on Photovoltaic Behavior of Polycrystalline Solar Cells

Structural, electrical, and photovoltaic properties of single impurity doped polycrystalline silicon were investigated in order to forecast the behavior of more complicated impurity matrixes, like those deriving from upgrading MG silicon. To this purpose, silicon was doped with increasing amounts of titanium, vanadium, chromium, iron, and zirconium, and the diffusion length of minority carriers was measured as a function of the impurity concentration and microstructural features like grain boundaries (GB), dislocations, twins, and stacking faults. Results are displayed in three‐dimensional diagrams which permit observations on the dependence of simultaneously with the impurity concentration and with the total density of electrically active structural defects.