Compact alcohol vapor sensor based on zinc oxide nanocoating deposited by Atomic Layer Deposition method on optical fiber end-face

摘要

Alcohol vapors sensitivity of a device based on a single mode optical fiber end-face coated with a thin zinc oxide (ZnO) film is presented. The overlays were deposited by Atomic Layer Deposition (ALD) method on both optical fiber tips and silicon reference wafers, and subsequently characterized by means of spectroscopic ellipsometry and scanning electron microscopy. It has been found that the ZnO films show very high quality and they are conformal over the surfaces. The thin ZnO film forms a Fabry-Perot interferometer at the fiber end-face which properties change when the tip is exposed to alcohol vapors. The response of the structure to isopropanol vapors is shown and discussed for different thickness of the ZnO film.