Research On Room Temperature Thin Film Hydrogen Microsensors

Hydrogen (H2) is widely used in large quantities in industries. Detection and measurement of H2 in a reliable and efficient manner is of great value in these applications, not only from safety concerns but also economically beneficial. Hence a simple but efficient hydrogen sensor is urgently demanded.In this work, a new type semiconductor Materials, La2O3-Ni, formed as nanofilm are proposed to be used as semiconductor sensitive element of hydrogen sensor. The La2O3-Ni nanofilm hydrogen sensor can have good response to hydrogen at room temperature because the La2O3-Ni nanofilm has high catalyst ability and specific surface area (BET).The sensing layer was deposited onto silicon wafer. Thin layers of the oxides were obtained by vacuum evaporation and thermal treatment. It was found that the oxide films behaved as an n-type semiconductor. The surface morphology was studied using AFM and X-ray photoelectron spectroscopy. The thin film was exposed to hydrogen and Carbon monoxide orderly. At room temperature operation and in the presence of ambient humidity, the sensors generally showed good response for hydrogen, but easily poisoning for carbon monoxide.This experiment has provided interesting and challenging results for new sensing films in metal oxide gas sensor technology. The great advantages of the new type room temperature thin film hydrogen microsensors are listed as follow:1, Working temperature of this type hydrogen sensor is at room temperature, and heating isn't the necessary part.The hydrogen sensors work at room temperature can bring a lot of advantages, the most important of them are:a. the better security;b. the lower power consumption;c. the longer life;d. the simple electrocircuit design.2, Response to hydrogen is stable.3, Repeatability and reproducibility are good.However, further investigations are needed to improve the stability and selectivity of the new sensor.