InxGa1-xAs Nanowires on Silicon: One-Dimensional Heterogeneous Epitaxy, Bandgap Engineering, and Photovoltaics - SHIN, Jae Cheol; KIM, Kyou Hyun; KI JUN YU; HEFEI HU; LEIJUN YIN; NING, Cun-Zheng; ROGERS, John A; ZUO, Jian-Min; XIULING LI (Nano letters, 2011)