Spin rate influenced structural and optical characteristics of Zn0.95Al0.03Ni0.02O thin films

Abstract

The film formation, structural, optical and electrical characteristics of spin coated films are governed by the various processing parameters. Hence it is indeed necessary to examine the consequence of various deposition parameters of spin coating method. Using the spin-coating method transparent Zn0.95Al0.03Ni0.02O thin films were coated on a glass substrate. The spectroscopic and analytical methods are used to examine the importance of spin rate on the optical and structural characteristics of deposited thin films. The prepared thin films are having a favoured c-axis orientation of crystallites, which deteriorates as the spin rate increases. Furthermore, the observed peak shift to higher Bragg angle and decrease in intensity peaks with spin rate indicates the films have a higher crystallinity. In order to assess the effect of spin rate, various structural parameters (such as, crystallite size, stress, lattice micro-strain, dislocation density and lattice constants) were estimated using various analytical equations. The size of the crystallites was discovered to decrease as the spin rate of the substrate increased. The optical properties of the films show that they are having transparency about 90 % in the visible wavelength region. The ultra-violet peak observed to be redshifted with spin rate shows decrease in the value of band gap energy. The results suggest that the optical and structural characteristics can be tailored by changing the spin rate, which are the potential candidates for the optoelectronic devices.