Dielectric and ac conductivity studies in as‐grown Ga2Te3 crystals with the defect zinc‐blende structure

Abstract

AbstractGa2Te3 crystallizes in the zinc‐blende structure where one‐third of the cation sites are vacant. The dielectric properties of as‐grown Ga2Te3 crystals have been studied in the frequency range from 102 to 109 Hz. Below room temperature, the dielectric constant is around 20 and almost independent of temperature. The ac conductivity is found to obey a power law σac ∼ ωs, with s ∼ 1 indicating that the conduction is due to hopping of localized charge carriers. Above room temperature the dielectric constant shows an S‐shaped step‐like increase up to a very large value around 104. The relaxation is found to be of thermal activated Debye type, the relaxation time changes as $\tau = \tau _0 \,{\rm exp}(E_\tau /kT)$ ($E_\tau \approx 0.27\,{\rm eV}$). The activation energy of the relaxation nearly coincides with that deduced from conductivity. These results are analyzed using the Maxwell Wagner model and the space charge model.