Dielectric Properties of Tl-Doped GaSe Single Crystals: Frequency Dispersion and Relaxation Processes

Abstract

Abstract – The dielectric properties of Tl-doped ε-GaSe (ε-GaSe〈Tl〉) single crystals in alternating electric fields were investigated. The frequency dispersion of the complex dielectric permittivity was analyzed using the Havriliak–Negami (HN) formalism in combination with the complex dielectric modulus approach. The main dielectric relaxation parameters, including the characteristic relaxation time, spectral width and asymmetry, as well as the high-frequency dielectric permittivity, were determined. It is shown that the combined use of HN analysis and the modulus formalism enables a reliable evaluation of the defect lifetime distribution even in the presence of a significant contribution of electrical conductivity to the dielectric response of ε-GaSe〈Tl〉.