The expression "n-type solar cell" refers to cells for which n-type silicon wafers are used. The starting material (Si feedstock) for producing n-type silicon wafers is the same as the one used for p-type Si crystals. The difference is in the doping process during crystallization: while for p-type Si, group III dopants (e.g. Boron) are used, for n-type Si crystals Group V dopants (e.g. Phosphorous) are used.
In a typical semiconductor, there might be $10^{17}~\mathrm{cm^{-3}}$ majority carriers and $10^6~\mathrm{cm^{-3}}$ minority carriers. In n-type semiconductors, the majority carriers are Negatively charged electrons whereas in p-type semiconductors, the majority carriers are Positively charged holes.
N-type does not refer to a semiconductor with 1 doping but to the negatively charged majority carriers.
N-type silicon has a better tolerance to common impurities, e.g. Fe, and potentially results in higher minority carrier diffusion lengths compared to
p-type substrates with a similar impurity concentration. Moreover, n-type Si does not suffer from the boron-oxygen related light-induced degradation LID.