Investigation of the optical properties of sputtered ZnO films by reflectance spectroscopy

Abstract

ZnO films have been deposited on SiO(2)/Si substrates by rf magnetron sputtering. The rms roughness of the sample's surface was surveyed by using an atomic force microscope, and is less than 10 nm. The theoretical reflectance of the air/film/middle layer/substrate structure has been deduced. In the light of this theoretical reflectance, the complex refractive index n ( lambda ) = n ( lambda) + ik ( lambda ) of the sample below the interband absorption edge has been fitted with a Lorentz oscillator model. The absorption coefficient alpha ( lambda ) of the sample is reported, and the result shows the sample has weak absorption around 490 nm. (c) 2006 Society of Photo-Optical Instrumentation Engineers