AC conductivity and dielectric parameters studies in multilayer TiO2/ZnO thin films produced via ALD technique

Abstract

In this paper, the effect of frequency and temperature on AC conductivity and dielectric parameters of multilayered TiO2/ZnO thin films have been reported. Among other techniques, the multy layer deposition (ALD) seems to be a promice approach. The fabricated multilayer thin films were grown on Si (100) substrate at 373 K and were nominally 100nm thick with alternating TiO2 and ZnO layers of varying number and thickness. AC conductivity and dielectric studies of different thin films were studied in the frequency range of 100 Hz – 1 MHz and the temperature range of 303 K to 393 K.The observed behavior of AC conductivity and frequency exponent s,on frequency and temperature, can be understood on the basis of correlated barrier hopping (CBH) model. The value of the maximum barrier height Wm has been determined. The analysis of the dielectric constant ε1 and the dielectric loss ε2 reveals their dependence on the frequency and the temperature. The main goal of this study is to evaluate how the thickness and the number of TiO2/ZnO bilayer affects the dielectric properties, which allows us to positively influence the electrical properties of the multilayer. The imply results based on AC conductivity and dielectric properties can be utilize in the future to improve the desirable properties of lightweight electronic and optoelectronic devices.