AC conductivity and dielectric properties of Se70Ge30-xMx {x=0&5 and M=Ag, Cd or Pb} amorphous films.

Abstract

The temperature and frequency dependences of ac conductivity σ (ω) ac , dielectric constant ε ′(ω) and dielectric loss ε ′′(ω) are studied for Se70Ge30, Se70Ge25Ag5, Se70Ge25Cd5 and Se70Ge25Pb5 amorphous films, in the temperature range 313-453 K and frequency range 0.1-100 kHz. The obtained data reveals that σ (ω) ac for all investigated compositions is temperature dependent, and obeys A\ω S law. The temperature dependences of σ (ω) ac and the frequency exponent S are exlained on the basis of correlated barrier hopping CBH model. Analysis of the results reveals that the electronic conduction for all investigated compositions takes place via bipolaron hopping at temperatures range 313K – 363K, and single polaron hopping at temperatures range [373K – 453K]. Also, it has been observed that ε ′(ω) and ε ′′(ω) exhibit strong temperature and frequency dependencies for all investigated compositions.