A thin film solar cell and process for forming the same. The solar cell includes a bottom electrode layer, a light absorbing semiconductor layer, and top electrode layer. The absorber layer includes a p-type interior region and an n-type exterior region formed around the perimeter of the layer from a modified native portion of the p-type interior region, thereby forming an active n-p junction that is an intrinsic part of the absorber layer. The top electrode layer is electrically connected to the bottom electrode layer via a scribe line formed in the absorber layer that defines sidewalls. The n-type exterior region of the absorber layer extends along both the horizontal top of the absorber layer, and onto the vertical sidewalls of the scribe line to increase the area of available n-p junction in the solar cell thereby improving solar conversion efficiency.