MoS₂ナノ粒子のインクジェットプリントを応用した静電容量型ガスセンサの作製

抄録

A capacitive MEMS gas sensor is fabricated by transfer printing of Au thin film and inkjet printing of molybdenum disulfide (MoS₂) nanoparticles. The transferred Au thin film is formed to be a comb electrode with a width of 100 μm and a thickness of 50 nm, and the comb-like Au electrode surface becomes hydrophilic by UV irradiation. The MoS₂ particles are deposited on the comb-like Au electrode as a sensing element, where the applied voltage and the pulse width of the piezoelectric inkjet head are adjusted to make a drop velocity of 6 m/s. The UV irradiation helps the MoS₂ particles to be deposited uniformly while suppressing undesired aggregation of the particles. The fabricated sensor composed of the comb-like Au electrode and the film of MoS₂ particles is placed in a chamber for testing, and the capacitance is measured with exposure to ethanol gas. It is demonstrated that the capacitance increases with exposure to ethanol gas and subsequently decreases after air-exposure. It is reasonable that the capacitance change is due to the adhesion of ethanol gas molecules to the MoS₂ particle film, and that the fabricated structure works as a capacitive MEMS gas sensor. It is also found that there are variations in response due to the surface morphologies of the MoS₂ particle film.