Optical transmittance study by Using a modified envelope analysis for Al-ZnO thin films

In this study, we investigated the optical transmittance of Al-doped ZnO (AZO) thin films. As the first step, we deposited AZO films on glass substrates and measured the optical transmittance in the wavelength range from 200 nm to 800 nm in order to determine the optical constants of film (the absorption coefficient, the extinction coefficient and the refractive index). Using these parameters, we calculated and simulated the average transmittance in the visible wavelength range as a function of the films thickness by means of modified envelope analysis (MEA) method. As a simulation result, the first maximum transmittance appeared for a thickness of 151 nm and oscillated with a thickness period of 151 nm. Then, we compared the experimental transmittance data with do to obtained by using the MEA method for species of AZO films deposited with variation of film thicknesses. We confirmed that the experimental average optical transmittance agreed well with the theoretical transmittance simulated by using the MEA method.