Solution Processed AZO Thin Films Prepared from Different Source Materials

Abstract

Aluminum doped Zinc Oxide films were spin-coated from 1 mol% doped precursors obtained from different source materials optimizing post-deposition annealing in controlled atmospheres. AZO films were provided with pre-deposition heating at 500 °C in ambient while post-deposition rapid thermal annealing (RTA) in vacuum and in N2-5%H2 was provided at 400, 500 and 600 °C. Dominant ZnO c-axis oriented AZO films with typical wurtzite crystal structure were obtained. Aluminum nitrate source materials resulted in comparatively higher conductivity AZO films. We conclude post-deposition annealing in controlled environments helped increase oxygen vacancies and enhanced grain growth and crystallinity resulting in increased conductivity. Optical measurements showed an average total transmittance (%T) of about 85 % in the visible for all the films with a direct allowed band gap of about 3.2.