**Abstract**

Photovoltaic (PV) technology could be a promising candidate for clean and green source of energy. The nanowire technology provides extra mileage over planar solar cells in every step from photon absorption to current generation. Indium Gallium Nitride (InxGa1-xN) is a recently revised material with such a bandgap to absorb nearly whole solar spectrum to increase the conversion efficiency copiously. One of the major technological challenge is in-built polarization charges. This chapter highlights the basic advantageous properties of InxGa 1*−x*N materials, its growth technology and state-of-the-art application towards PV devices. The most important challenges that remain in realizing a high-efficiency InxGa 1*−x*N PV device are also discussed. III-Nitride nanowires are also explored in detail to overcome the challenges. Finally, conclusions are drawn about the potential and future aspect of InxGa 1*−x*N material based nanowires towards terrestrial as well as space photovoltaic applications.

**Keywords:** III-nitride, polarization charges, efficiency, InGaN/GaN, nanowires, stress, strain
