High-Frequency Conductivity of Amorphous and Crystalline Sb2Te3 Thin Films

Abstract

The results of study of charge transfer processes in thin amorphous and crystalline Sb2Te3 films in a wide range of frequencies and temperatures are presented. The frequency spectra of conductivity were obtained by the dielectric spectroscopy method. The authors analyzed the frequency dependences of the conductivity in the electric field and the temperature dependences of the exponent s. A transition from the classical correlated barrier hopping (CBH) to quantum mechanical tunneling (QMT) was observed at a certain temperature Tt. The CBH model allowed the authors to calculate the conductivity parameters of two phases. Two areas with different types of conductivity were revealed on the conduction spectra, and the activation energies of charge transfer processes for amorphous and crystalline films were determined. The following features were discovered: the difference in the temperatures of the change of the charge transfer mechanism and the transition from the semiconductor region to the metal region on the temperature dependence of conductivity. They can help to identify the amorphous phase in the quasi-binary chalcogenide Sb2Te3-GeTe system.