Photoconduction in the Peierls conductor monoclinic TaS3

Photoconduction in the monoclinic phase of quasi-one-dimensional conductor TaS3 has been observed at T<70K. It was studied jointly with low-temperature ohmic and non-linear dark conduction. The strong sample quality dependence of both photoconduction and dark conduction at this temperature region has been observed. Together with a similarity of the main features of the photoconduction characteristic of both monoclinic (m-TaS3) and orthorhombic (o-TaS3) samples the following new peculiarities of photoconduction in m-TaS3 were found: (1) the dependence of the activation energy of photoconduction on temperature, T, (2) the change of the recombination mechanism from the linear type to the collisional one at low T   with a sample quality growth, and (3) the existence of a fine structure of the electric-field dependence of photoconduction. Spectral study gives the Peierls energy gap value 2Δ⁎=0.18eV.