Abstract
Ternary Cu-Bi-S based compounds have been thought to be alternative materials for well-known CuInS2 because of their abundance. Cu-Bi-S based nanomaterials have been less studied. We here report the synthesis, optical and electrical properties of single crystal Cu4Bi4S9 nanowires. High-quality Cu4Bi4S9 nanowires were synthesized through a modified solvothermal route by controlling the reaction sources and temperature. The optical bandgap for Cu4Bi4S9 nanowires were determined by using UV-vis-NIR and cyclic voltammetry techniques. Single nanowire devices were fabricated by using lithographic techniques. The devices exhibit photoconductive response with high external quantum efficiency (2.9 x 10(8)%). Temperature-dependent electrical transport properties were also investigated. We observed that the transport properties of Cu4Bi4S9 nanowire show typical semiconductor behaviour in the temperature region 10-140 K and metal-like character in the temperature region of 150-300 K. The carrier transport in Cu4Bi4S9 nanowires can be described by the small polaron model in temperature region of 60-140 K and the variable range hopping mechanism in temperature region of 10-50 K. We further studied the properties of Cu4Bi4S9 nanowires in field-emission devices. The devices exhibit a relatively low turn-on field (6.9 V mu m(-1)). The potential applications of Cu4Bi4S9 nanowires as field emitting materials and light absorbers in detectors are indicated.