Properties Of Multilayer Transparent Conductive Films Prepared By RF Magnetron Sputtering Using Powder Targets

Transparent conductive oxide(TCO) films show various excellent optical and electrical properties and abroad applied background. Conventional TCO films which are limited by the semiconductor conductive mechanism can no longer meet the increasing requirements. To meet the expectations for growing demand, there is a need to develop alternative low-cost, but high-quality transparent electrodes with properties comparable to the conventional TCOs. The high conductivity and transmittance of TCO/metal/TCO multilayer structures have attracted intensive studies in recent years. The metal layers ensure the conductivity in these TCO/metal/TCO multilayer structures, while the high refractive index of TCO layers guarantee the transmittance within the visible light due to their anti-reflection effect.TCO/metal/TCO films have emerged as a good alternative because they provide optical and electrical characteristics globally superior to those attainable with a single-layer TCO and can be deposited at low temperatures onto inexpensive plastic substrates. It becomes significant to study the preparation technology of TCO/metal/TCO multilayer films.Magnetron Sputtering is one of the most popular techniques to prepare TCO films. The single-layer and multilayer films were prepared on glass, polyimide(PI)and PI/graphene substrates by RF magnetron sputtering using the powder AZO target and the solid Ag target at room temperature. The purpose of this thesis is to study properties of the multilayer transparent conductive films deposited on different substrates using powder targets. The morphology and crystallinity, as well as the optical and electrical properties of the films were examined by using different characterization equipments, including X-ray diffraction, Atomic force microscopy,UV-visible spectrophotometer and Hall-effect measurement. The results showed that the as-deposited multilayer films were polycrystalline on different substrates. Ag layer with the cubic structure had a preferred orientation of(111) and AZO layers with the hexagonal structure had a preferred orientation of(002). The morphology of the films on glass substrates exhibited smooth surface, uniform grain size and defect-free structure. The optical and electrical properties of multilayer films were optimized by optimizing the Ag layer thickness and AZO layer thickness. The thickness of the Ag layer was the main factor to affect the optical and electrical properties of AZO/Ag/AZO films. The thickness of AZO layer had a certain effect on the optical properties of the trilayer films. When the thicknesses of AZO/Ag/AZO films were30 nm of AZO and 14 nm of Ag layers, the sheet resistances were as low as 2.6Ω/□ and4.6Ω/□ on glass substrates and PI substrates, respectively. The transmittances of the films at 550 nm were 85% on glass substrates and 70% on PI substrates. When the thicknesses of PI/graphene/Ag/AZO films were 65 nm of AZO and 15 nm of Ag layers,the transmittance of the film at 550 nm was 35% and the sheet resistance was 200Ω/□.The AZO/Ag/AZO films showed their very good conductivity and reasonable highlight transmittance on both glass and PI substrates. The advantages of this approach to prepare the films were environmental friendly, with low cost and at low temperature.