Dielectric and ac conductivity studies in as-grown Ga2Te3crystals with the defect zinc-blende structure

✍ Scribed by Seki, Y. ;Kusakabe, M. ;Kashida, S.

• Book ID: 105365550
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 617 KB
• Volume: 207
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200925354

✦ Synopsis

Abstract

Ga~2~Te~3~ crystallizes in the zinc‐blende structure where one‐third of the cation sites are vacant. The dielectric properties of as‐grown Ga~2~Te~3~ crystals have been studied in the frequency range from 10^2^ to 10^9^ 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 σ~ac~ ∼ ω^s^, 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 10^4^. 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.