The characteristics of aluminium-doped zinc oxide films prepared by pulsed magnetron sputtering from powder targets

Abstract

Mixed zinc oxide and alumina powder targets have been used to prepare transparent semi-conductive films on glass by pulsed magnetron sputtering. The structure, crystallinity, optical properties, electrical properties and adhesion of the films were investigated using a range of techniques, including SEM, XRD, spectrophotometry, four-point probe and scratch adhesion testing. Also, the properties of the coatings before and after annealing under various conditions are compared. The crystallinity of the films increased and the preferred orientation in some of the samples changed from (1 0 0) to (0 0 2) after annealing. The transparent lines of the coatings showed blue shifts with the average transmittance within the visible range being up to 90%. Resistivities of the order of 10 −3 Ω cm were obtained after annealing, without deterioration of the coating-to-substrate adhesion. The results to date demonstrate that the pulsed magnetron sputtering of Al-doped ZnO films from powder targets is a versatile, novel technique for the deposition of high quality transparent conductive oxide materials. As a demonstration of the flexibility of this technique, preliminary results from an investigation into indium-doped zinc oxide coatings are also included here.