Growth and characterization of multicrystalline silicon ingots by directional solidification for solar cell applications

This study is focussed on the growth of multicrystalline silicon ingots with large grains by controlling the
silicon melt cooling rate to initiate dendritic nucleation in the initial stage of the solidification. Two ingots
were grown with different undercooling rates and compared with a reference ingot grown by standard
cooling conditions. All ingots were grown in a lab scale directional solidification system. The wafers cut
from all three ingots have been characterized for resistivity, minority carrier lifetime and dislocation
density measurements by four point probe, quasi steady state photo conductance and PV Scan,
respectively. The wafers were converted into solar cells and their electrical parameters have been
measured. The cells fabricated from ingot 2 show slightly higher efficiencies in comparison with ingot 1
and the reference one. The present cooling rate was not enough to initiate the dendrite nucleation in the
beginning of the solidification. Hence, there is no significant difference was observed in the crystal
quality of the grown ingots 1 and 2.