Free-electronlike diffusive thermopower of indium tin oxide thin films

We report our measurements of thermopower, S(T), on a series of indium tin oxide thin films from 300 down to 5 K to extract the carrier concentration n. The temperature behavior of S (T) below 300 K can be essentially described by a prevailing linear diffusive contribution. In this wide temperature interval, the phonon-drag thermopower is negligible relative to the diffusive thermopower. Therefore, the free-electronlike characteristic is clearly addressed. It should be stressed that linearity in S_d from liquid-helium temperatures all the way up to room temperatures is seldom seen even in simple metals.