THERMOELECTRIC-POWER BEHAVIOR IN CARBON NANOTUBULE BUNDLES FROM 4.2 TO 300 K

Thermoelectric power (TEP) properties of carbon nanotubule bundles wer e measured in the range 4.2-300 K. It was found that the TEP is positi ve over the whole temperature range, and increases with the increase o f temperature. Above 30 K it can be well described by a formula S(mu V ) = 0.181T- (61.8 + 0.092T)e (-308.3/T) which is derived based on a tw o-band model. This result supports the theoretical prediction for both kinds of nanotube bundles, metallic and semiconducting. Below about 3 0 K, the fitting curve clearly deviates from the experimental data, wh ich may indicate some possible changes of electronic structures, an el ectron weak localization effect, for example. [S0163-1829(98)00324-5].