Create my own solar cells?
You have to study existed architectures. First, it is necessary to distinguish between photo-conductive and photovoltaic elements. In photovoltaic elements one needs a mechanism of separation of positive and negative charges formed under an irradiation of the semiconductor. Even a simple p-n junction can do this. But, this is all about efficiency. The solar cell has to absorb as much light as possible without reflections, and, at the same time, the charge transport inside should be without losses that is impossible in thick structures. Also we have to care about the absorption spectrum. To absorb in all spectrum of the solar radiation, people make cascade structures with different materials absorbing in different ranges of spectrum.