Hall effect in ClO/sub 4/- doped polythiophene and poly(3-methylthiophene)

Summary form only given. We have studied the temperature dependence of the Hall effect and the resistivity for Cl0/sub 4/- (as-grown) doped polythyophene (PT) and Poly(3-methylthiophene) (PMeT) films. For both samples, the sign of Hall coefficient is positive between 4.2K to 300K, consistent with the acceptor doping and the thermoelectric power data previously reported /sup [1]/. Near the room temperature, the Hall coefficient of PT and PMeT has a magnitude of about 8x10/sup -10/M/sup 3//C (PT) and 2x10/sup -10/m/sup 3/C (PMeT), respectively. The free-electron model leads to the carrier density of 8x10/sup 21/ /cm/sup 3/ (PT) and 1x10/sup 22/ /cm/sup3/3 (PMeT), which is not consistent with other estimates of the electron density. Below the room temperature, the Hall coefficient of PT increases markedly with decreasing temperature, reaching a magnitude of about 10/sup -5/M/sup 3/C near 4.2K.