Published online by Cambridge University Press: 01 February 2011
The thermoelectric power of bismuth nanowires is theoretically calculated to be greatly enhanced over that of bulk Bi. This is a result of the size-quantization of the electron wavefunction in nanowires with diameters below 50 nm. The effect is expected to lead to the development of high figure of merit thermoelectric materials. We review here the experimental observation of such enhancement in composites containing nanowires with diameters down to 9 nm. When the wire diameter is further decreased, localization effects take over and limit the thermopower. The theory further predicts the appearance of an energy gap in bismuth nanowires with diameters below 50 nm. We observe such a gap in the temperature dependence of the resistivity. The dependence of the gap on nanowire diameter is consistent with theory. Comparisons of the transport properties of Bi nanowires with those in other nanowire systems show the influence of localization effects.