GaInN has the potential to revolutionize the solar cell industry, enabling higher efficiency solar cells with its wide bandgap range spanning the entire solar spectrum. However, material quality issues stemming from the large lattice mismatch between its binary endpoints and questionable range of p-type doping has thus far prevented realization of high efficiency solar cells. Nonetheless, amorphous and multi-crystalline forms of GaInN have been theorized to exhibit a defect-free bandgap, enabling GaInN alloys at any indium composition to be realized. But the range of possible p-type doping has not yet been determined and no device quality material has been demonstrated thus far. Nonetheless, a Schottky barrier design (to bypass the p-type doping issue) on single-crystal GaInN can be used to provide some insight into the future of amorphous and micro-crystalline GaInN Schottky barrier solar cells. Through demonstration of a functional single crystalline GaInN Schottky barrier solar cell and comparison of the results to the best published reports for more conventional p-i-n GaInN solar cells, this work aims to establish the feasibility of amorphous and multi-crystalline GaInN solar cells. / Ph. D.