Optical and electrical properties of thermally deposited aluminium thin films

Abstract

Thin film coatings can be applied to windows in buildings for solar control and energy-saving purposes. By regulating the solar radiation entering through windows in spectrally selective manner, it is possible to save energy that would be used for air conditioning and promote indoor comfort. The research investigated optical and electrical properties of aluminium thin films and their application in energy effective windows. The basic energy benefit of window films is reducing infrared solar heat gain. The quantity of savings which will be produced by the aluminium film bases on its level of infrared reflectivity, the thermal energy properties, the exposure of the window and the climate where the building is located. The aluminium thin films were successfully deposited on glass slide substrates by thermal evaporation using the Edwards Auto 306 vacuum coater, the deposition angles of films were altered using an adjustable substrate holder (angle rotator) in the vacuum coater ranging from 00 to 800 at intervals of 100 . The optical and electrical properties of aluminium thin films were determined using the Lambda 19 UV/VIS/NIR spectrophotometer and the Jandel multiheight four point probe, respectively. The film thickness was determined using the thickness monitor and scout software. The reflectance, absorbance and conductivity of the films increased with increase in film thickness. The sheet resistance and resistivity of the films decreased with increase in film thickness. The reflectance and conductivity of the films decreased with increase in deposition angle while the absorbance, sheet resistance and resistivity increased with increase in the deposition angle of the films. Films with thickness 250 nm and those deposited at 00 were recommended for application in window coatings. Also X-ray Diffraction needs to be done to study the structural properties of the aluminium thin films.