Fabrication of Nanoscale Multilayer Device by Filtered Cathodic Vacuum Arc for Optical Application

Abstract

Multilayer device with 8 nano-layers consisting of alternate TiO2thin films (high refractive index) and Al2O3thin films (low refractive index) have been successfully fabricated by filtered cathodic vacuum arc (FCVA) with two separate cathodic sources. Microstructure and element distribution of multilayer coatings were examined by TEM and electron energy loss spectroscopy (EELS), respectively. The results show that the interfaces of the layers are well defined and exhibit smooth, sharp and flat properties. Each layer with nano-thickness keeps amorphous structure as determined by the electron diffraction pattern and XRD. The bond nature in respective TiO2and Al2O3layers is Ti⁴⁺-O^2-and Al³⁺-O^2-and no atoms diffuse into the nearby layer as concluded by EELS measurements. Good homogeneity in microstructure and element distribution indicates the potential deposition of multilayer by FCVA for advanced performances including optical application.