Al-doped ZnO/Ag/Al-doped ZnO multilayer films with a high figure of merit

Abstract

In this study, we investigated the effects of the Al-doped ZnO (AZO)-layer thickness on the optical and electrical properties of AZO/Ag/AZO multilayer films deposited on glass substrates at room temperature. The optimal AZO/Ag/AZO (36 nm/19 nm/36 nm) multilayer sample exhibited a transmittance of approximately 93% at 550 nm. As the AZO-layer thickness increased from 9 to 45 nm, the carrier concentration gradually decreased from 1.87 x 10(22) to 6.36 x 10(21) cm(-3), while the sheet resistance slightly increased from 3.86 to 4.47 Omega sq(-1) and the charge mobility increased from 24.15 to 25.42 cm(2) V-1 s(-1). The samples had smooth surfaces with a root mean square (RMS) roughness ranging from 0.40 to 1.23 am. The Haacke figure of merit (FOM) was calculated for the samples as a function of the AZO-layer thickness. The optimal AZO/Ag/AZO multilayer film had the highest FOM of 99.9 x 10(-3) Omega(-1). (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.