Tailored Pd–Au layer produced by conventional evaporation process for hydrogen sensing

Here we propose two methods using conventional evaporation process to produce tailored Pd/Au composite thin films for hydrogen sensing. In the first method Pd and Au are evaporated simultaneously using different evaporation rate. In the other, alternated nano-layer of Pd and Au are evaporated. Some characteristics of the thin films and their response to hydrogen when they are deposited over optical fibers are experimentally analyzed. Optical fiber sensors for detection of hydrogen concentration lower than 4% and response time of 10 s approximately are demonstrated. The possibility to precisely control the proportion of the constituents of Pd-alloys thin films to produce optical fiber hydrogen sensors with fast response makes these methods very attractive.

Research highlights
► This paper reports on the development of Pd–Au thin films for fast and sensitive hydrogen sensor.
► These thin films alloy are investigated in order to improve their response to hydrogen.
► The work deals with the use of the evaporation techniques to produce Pd–Au layers for hydrogen sensing.
► This work may open up new possibilities for optical sensing based on gas-sensitive nano-layers.