A solar cell can include a silicon layer formed over a silicon substrate. The silicon layer can have a P-type doped region and an N-type doped region. Portions of the silicon layer can have a grain size larger than other portions of the silicon layer. For example, larger grains of the silicon layer formed within a depletion region between P-type and N-type doped regions can minimize recombination loss at the P-type and N-type doped region boundaries and improve solar cell efficiency.