Frequency dependence of conductivity of bulk amorphous selenium and tellurium-doped selenium

The dc conductivity and ac conductivity of bulk amorphous selenium and selenium tellurides have been measured in the temperature range 150 to 310 °K. The ac conductivity is found to follow the relation ${\sigma }_{\mathrm{ac}}$ $\alpha {\omega }^n$, The value of $n$ is found to increase with the decrease in temperature and with the increase of doping of tellurium in selenium. The value of the density of states at Fermi level, $g\left(E_F\right)$ is also found to increase with the increase of tellurium doping. The results have been discussed with the existing theories for ac and dc conduction.