Raman studies of selenium nanowires under high pressure

The selenium nanowires with diameter of 70 nm and length of 40 μm were synthesized by a facile solution method. High-pressure behavior of Se nanowires has been investigated by in situ Raman scattering up to 20.2 GPa at room temperature. A reversible phase transition from hexagonal to monoclinic occurs at 18.1 GPa. This transition pressure is higher than that of 14.0 GPa for bulk Se. The intrinsic geometry and/or the increasing energy band gap of Se nanowires are considered to contribute to the increase of transition pressure.