Crystallographic characteristics and electrical properties of Al-doped ZnO thin films prepared by ionized deposition

Abstract

Aluminum-doped ZnO thin films were prepared by ionized deposition on glass substrates. The crystallinity and electrical properties of Al-doped ZnO films prepared by ionized evaporation depend on the deposition conditions. The c-lattice constant of ZnO films increases with ionization current and acceleration voltage. The spacing distribution of c-lattice planes varies inversely with the orientation distribution of the c axis, when deposition conditions such as ionization current, acceleration voltage, and substrate temperature are changed; the line width B002 of a (002) diffraction peak increases while the FWHM of rocking curve ΔΘ50 decreases. These changes of crystallographic characteristics cause a decrease in Hall mobility, and defects in the film resulting from ion bombardment cause a decrease in carrier concentration. Therefore, an increase in resistivity is observed in Al-doped ZnO films grown by ionized deposition. Ion bombardment during deposition must be minimized to avoid degradation of Al-doped ZnO films, because the properties of Al-doped ZnO films are significantly changed by ion bombardment of the film surface.