Study On The Properties Of Oxide Thin Films Fabricated By Atomic Layer Deposition

Atomic layer deposition (ALD) is a novel technique for manufacturing optical thin films. For this application, the most attractive feature of ALD method is that it is able to meet the needs for atomic layer control and conformal deposition using sequential, self-limiting surface reactions. In the present work, we investigated the properties of Al2O3, TiO2,Ta2O5ALD thin films versus growth temperature by depositing films on Si (100) and BK7substrates. Film thicknesses, growth rates, microstructure and optical properties were determined using SEM (scanning electron microscope), AFM (atomic force microscopy), XRD (X-ray diffraction), XPS (X-ray photoelectron), spectrophotometer and spectroscopic ellipsometry. We emphatically studied the dependence of optical characteristic on the structure of ALD deposited films. Good linearity features were observed at a certain temperature when the deposition cycle was varied from100to3000cycles, which indicated an excellent self-limiting characteristic during ALD growth. Because of the characteristics of ALD, transition regions always exist in interfaces, accompanying diverse growth rates. To avoid the thickness error caused by unstable growth rate, the pre-deposited layer is carried forward. With this method, a better agreement between the measured and calculated results of the multilayer coatings are achieved by ALD. Finally we use ALD thin films to encapsulate inverted indium-tin-oxide-free polymer solar cells (IFSCs) with a structure of Al/TiOx/P3HT:PC61BM/PEDOT:PSS. The results show much better device performance and higher stability than that of the glass-encapsulated structures.