Synthesis and Thermoelectric Property of Cu2−xSe Nanowires

Single crystalline Cu 2− x Se nanowires with lengths up to 50 μm are synthesized via a modified composite hydroxide mediated method. Experiments reveal that both quantity and species of hydroxides or amount of water used in the preparation would affect final morphology of Cu 2− x Se crystals, from nanoplates to nanorods to nanowires. The UV−visible−near-infrared reflection spectrum demonstrates the absorption edges of the Cu 2− x Se nanowires in the ultraviolet and near-infrared region, which could be interpreted in terms of direct transitions from a band gap of 2.38 eV and indirect transitions from a band gap of 1.12 eV. The band-to-band transition model has been proposed. In addition, Seebeck effect based on the Cu 2− x Se nanowire film is investigated, demonstrating the Seebeck coefficient of 180 μV/K.