Preparation of [111] -oriented CaO film through dehydration of a Ca(OH)2film

We successfully prepared [111]-oriented CaO films through deposition of a Ca(OH)2 film by a laser ablation method, followed by dehydration of the film. It should be noted that only [100]-oriented CaO film is formed by direct ablation of a calcium oxide target. The inplane orientation of the [111]-oriented CaO thin film was random as is the case of the calcium hydroxide film. The shrinkage of the thickness from calcium hydroxide to calcium oxide agreed very well with the calculated value, clearly indicating that calcium oxide is formed from calcium hydroxide by a topotaxy mechanism.