Thin Si solar cell with N type absorber based on epitaxial lateral overgrowth

Thin silicon (Si) solar cells have the potential of having high performance due to lower bulk recombination which leads to high open circuit voltage. It has been reported that the potential advantages of n type Si include longer lifetime, easier surface passivation, and no light-induced performance degradation. Therefore, a thin Si solar cell structure based on n type absorber is an important area to investigate for higher performance. Thin Si solar cells based on epitaxial lateral overgrowth (ELO) of the n type absorber have been previously reported. Open circuit voltage (Voc) is expected to be improved from utilizing an ELO solar cell due to reduced p-n junction area, which leads to a decrease in the dark saturation current. In this work, planar thin Si solar cells based upon n type epitaxial absorber have been fabricated and initial solar cell results have been analyzed. The processing steps developed for the planar solar cells will be transferred to the ELO solar cells. For the ELO solar cells, a more informative set of patterns have been designed, including different light generation area (A_L) to p-n junction area (A₀) ratios, different line orientations and different test patterns. PC1D software has been used to investigate the Voc and efficiency as a function of n type and p type Si absorber thickness, respectively.