Self-doping laser transferred contacts for c-Si solar cells

Laser transferred antimony contacts provide a self-aligned n-type selective emitter and simultaneously form the contacts to the front side of the solar cell. A pulsed laser beam transfers antimony from a transparent support through the passivation layer of a crystalline silicon solar cell and melts the underlying silicon. Antimony diffuses into the melt creating a locally highly doped n-type emitter. Between the transferred antimony contacts, the emitter remains shallowly doped, reducing Auger recombination. The antimony doped contacts act as seed layer for subsequent nickel and copper plating, resulting in a fine line front metallization with finger width w_F= 20 μm, contact resistivity as low as ρ_C= 30 μΩcm², and metallization resistivity ρ_M= 2.0×10^-6 Ωcm. First solar cells show an efficiency η= 17.5%.