Analysis of Reflectance and Transmittance Characteristics of Optical Thin Film for Various Film Materials, Thicknesses and Substrates

Md. Sultan Z and Sultana N

Abstract

Optical thin film can control the reflection, refraction and transmission of specific wavelength of electromagnetic radiation and have numerous applications such as reflector, anti-reflector, attenuator, photovoltaic cell and refractor in the electromagnetic radiation spectrum. To perform the particular function for which they are designed, precise control of various film parameters such as thickness, composition, roughness, uniformity is necessary. Silicon dioxide, Zinc oxide, Zinc telluride are the most promising materials in optoelectronic and optical applications in the visible region as well as in the infrared and UV region. In this research, the optical properties such as spectral reflectance and transmittance of nano-scale optical thin films have been studied and analyzed for those materials on different substrates to obtain the optimal configuration for the best performance. To obtain this, the equations of reflectance and transmittance for thin film have been derived, then simulated and visualized by Matlab code. By changing film materials, substrates and film thickness, transmittance and reflectance characteristics have been observed and analyzed. The result showed that the reflectance and transmittance characteristics of optical thin film are strongly dependent on the wavelength of electromagnetic spectra. The film and substrate materials are very effective on the reflectance and transmittance characteristics of the optical thin films. It is also found that the reflectance and transmittance characteristics are greatly affected by film thickness. This research work will benefit and enhance the value of nano coating technology to determine the best thin film/substrate configuration in the development of micro- and nano optoelectronic devices.

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