Improved performance of AZO/Ag/AZO transparent conductive films by inserting an ultrathin Ti layer

Abstract

Multilayer thin films of titanium-embedded Al-doped ZnO/Ag/Al-doped ZnO (AZO/Ag/AZO) structures have been designed and deposited onto polyethylene terephthalate (PET) substrates to develop an indium-free transparent flexible electrode. The effect of Ti layer on the morphological, structural, optical and electrical properties of multilayer thin films was investigated. The insertion of ultra-thin Ti layers enhances the near-infrared transmittance of AZO/Ag/AZO thin films, widens the spectral transmission window of AZO/Ag/AZO thin films, and improves the conductivity and surface roughness of AZO/Ag/AZO thin films. As the Ag thickness increases from 8 nm to 12 nm, the sheet resistance of the AZO/Ti/Ag/AZO thin film decreases from 16.22 Ω sq-1 to 7.17 Ω sq-1. AZO/Ti/Ag/AZO with an Ag thickness of 8 nm exhibits excellent optoelectronic properties with an average transmittance of 80.3 % and 61.7 % in the wavelength range of 400–1100 nm and 400–2000 nm, as well as a sheet resistance of 16.22 Ω Sq-1. It is demonstrated that AZO/Ti/Ag/AZO multilayer flexible films have great potential in various fields.