Investigation on optical and electrical properties of multilayer ITO/AZO/ITO transparent conductive oxides.

This paper examines how varying the thickness of the indium tin oxide (ITO) seed layer, ranging from 8 to 20 nm, impacts the optical, electrical, and structural properties of triple-layer transparent conductive oxide ITO/aluminum doped zinc oxide (AZO)/ITO. ITO and AZO films were deposited by DC and RF magnetron sputtering, respectively. The thickness and density of each layer were measured by X-ray reflectometry (XRR). X-ray diffraction showed that as the thickness of the ITO seed layer increased, both the average size of the crystallites and the volume of the crystalline phase in the AZO film also increased. Measurements of the electrical characteristics indicated a decrease in resistivity as the thickness of the ITO seed layer increased. This reduction is attributed to enhanced charge mobility, resulting from improved crystallinity. It has been shown that a 20-nm-thick ITO seed layer is sufficient to achieve a charge mobility comparable to that of pure ITO films. The photoluminescence spectra have shown a decrease in the concentration of the oxygen vacancies with the introduction of both the cover and seed layers of ITO. The figure of merits (FOM) of the triple-layer coatings and the optical constants of the AZO and ITO films were calculated. The results of this paper indicate that the ITO20/AZO48/ITO12 triple-layer coating possesses optimal characteristics for use in high-efficiency silicon solar cells. [Display omitted] • ITO seed layer with a thickness >8 nm improves AZO layer crystallinity. • 20 nm ITO seed layer enough to increase mobility from 9.56 to 41.34 cm2V−1s−1. • Introduction of ITO layers decreases concentration of oxygen vacancies in AZO layer. • ITO12/AZO48/ITO20 layer has the best FOM equal to 9.13 10−4 □ Ω−1. • 60–76 % replacement of ITO by AZO improves transparency in the region of 350–1100 nm. [ABSTRACT FROM AUTHOR]