The physical and chemical properties of semiconductor materials change drastically when its size is reduced to nanoscale due to their large surface area or quantum size effect. Metal oxide (MOx) semiconducting nanostructures hold the potential for playing a critical role in the development of a new platform for renewable energies, including energy conversion and storage through photovoltaic effect, solar fuels, light-emitting nano devices, laser technology and water splitting. Further development of nanotechnology will certainly lead to significant breakthroughs in the semiconductor industry.