Effect of Thickness on the Optical Properties of Al-Ni-Cr Thin Films Prepared by Thermal Evaporation Technique

Al-Ni-Cr thin films with different thickness (18, 26, and 30 nm) were prepared by thermal evaporation technique on glass substrates under vacuum of 10-7 mbar. The influences of the thickness on the optical properties of Al-Ni-Cr thin films were mainly investigated from recording the absorbance and transmittance spectra by UV-Visible spectrophotometer in the range of 200-1100 nm. From these spectra, the transmittance decreased with increasing of thickness, while the absorbance increased with increasing of thickness. The values of optical energy gap decreases from 1.8 to 0.73 eV when thickness increased from 18 to 30 nm. The optical conductivity increased with increasing thickness.