Obviating the post annealing step for production of Al-doped zinc oxide films using sol–gel method: Use of rapid cooling and gas blanketing

• Effect of rapid cooling and gas blanketing on sol–gel derived AZO films was studied.
• AZO films prepared by conventional post-annealing treatment and our method were compared.
• Rapid cooling and gas blanketing showed significant improvement in electrical properties.
• Optical, crystalline and structural properties remain unaltered by this treatment.

In this work a method has been presented for preparation of sol–gel derived transparent conductive Al-doped zinc oxide (AZO) films. This method is based on rapid cooling of the glass in the presence of a gas blanket and does not require the post annealing step. Rapid cooling is used to kinetically limit the oxygen diffusion to the film and gas blanketing has been used to enhance the effect. Gas blankets have been generated by placing the hot AZO coated glass on a gas evolving material (e.g. ammonium carbonate) which generates gas by endothermic reaction. Rapid cooling has been shown to be only slightly effective and combined rapid cooling and gas blanketing has been shown to be a good combination. AZO films (100 nm thick) prepared by this method show low resistivity (5.4 × 10− 2 Ω ‐ cm), high transmittance (> 90%), and preferential crystalline orientation [002] comparable with conventionally post-annealed AZO film in forming gas atmosphere.