High Lifetime Ga-Doped Cz-Si for Carrier Selective Junction Solar Cells

Industrial mass production of solar cells is moving towards carrier selective junction solar cells with passivating contacts such as TOPCon, POLO and HJT solar cells. At the same time many manufacturers consider switching from p-type Cz-Si to n-type Cz-Si wafers. This contribution indicates that Ga-doped p-type Cz-Si material is still a viable option for the new type of devices while giving an opportunity to benefit from 8-10% lower wafer cost. In that respect a Ga-doped Cz-Si ingot has been specified and characterized. We report minority carrier diffusion lengths that are an order of magnitude larger than the thickness of the studied HJT and TOPCoRE devices. So far best p-type HJT solar cells perform 0.2 % absolute lower in efficiency than co-processed n-type reference HJT solar cells. Best TOPCoRE solar cells on Ga doped Cz-Si, however, show a 0.2% to 0.3% higher efficiency than their co-processed n-type TOPCon counterparts.