Dual-layer ultrathin film optics: II. Experimental studies and designs. (16th February 2015)

• Record Type: Journal Article
• Authors: Lim, Kim Peng; Wang, Qian
• Is Part Of: Journal of optics. Volume 17:Number 3(2015:Mar.)
• Publication Date: 2015-02-16
• Subjects: dual-layer ultrathin film -- ion-beam deposition -- antireflection; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8978/17/3/035614
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: This paper presents an experimental study of using dual-layer ultrathin films with a high refractive index and low refractive index to approximate a single-layer thin film with an equivalent intermediate refractive index, which is the basis of the functional graded refractive index thin film stack using dual-layer ultrathin films. Using ion beam deposition, five sets of ultrathin films of titanium dioxide (TiO2 ) and aluminium oxide (Al2 O3 ) are deposited on silicon with different volume fractions and characterized by spectroscopic ellipsometer for the ordinary/extraordinary refractive index and by spectrophotometer for the reflectance. By designing the sequence of TiO2 and Al2 O3 ultrathin films, the measured results show a good agreement between the experiments and simulation of the equivalent birefringent thin film. An application example of using the TiO2 and Al2 O3 dual-layer ultrathin films to approximate a single-layer antireflection coating for silicon is presented.