Cu_2O and CuO are typical p-type semiconducting oxides and thus promising for gas sensors. However, heat-treatment necessary for sintering Cu_2O powder into porous thick films in air changes Cu_2O to CuO. As a result, it is not possible to prepare Cu_2O sensors. To this connection the reversible transformation between Cu_2O and CuO is examined. It turns out that CuO can be brought back to Cu_2O by holding CuO in an ambient of ethanol-added air at 330℃ for 1 hr. However, the Cu_2O sample thus obtained is found to be rather insensitive to reductive gases. The CuO samples prepared by sintering Cu_2O in air are satisfactorily potential as p-type semiconducting oxide sensors.
福井工業大学研究紀要. 第一部 34 47-52, 2004-03-20