III–V Semiconductor Single Nanowire Solar Cells: A Review

III–V semiconductor nanowires have gained intensive attention for solar cell applications due to their unique geometrical, optical, and electrical properties, as well as improved accessibility to a wider range of alloy compositions (and thus tunable bandgaps) and substrates (such as Si), which allows further exploration and implementation of various tandem solar cell designs to broaden and more efficiently harvest the absorption of the solar radiation. Herein, the development of this field with emphasis on single nanowire-based solar cells is reviewed. First, nanowire synthesis methods are introduced, followed by important aspects of single nanowire fabrication and design consideration for high power conversion efficiencies (PCEs) in terms of light absorption and charge carrier separation and collection. Then, the reported nanowire solar cell performance based on different III–V semiconductor nanowire materials and structures is presented and analyzed. Finally, the strategies toward high efficiency and low cost solar cells are discussed.