The gas-sensing of GdCoO3/MOx (M = transition metals) element having a heterojunction

The I–V characteristics and sensing properties are investigated for LnCoO3/MOx (Ln=Sm, Gd, M=Fe, Zn, In, Sn) element prepared by mechanically contacting two sintered pellets. For SmCoO3/Fe2O3 and GdCoO3/ZnO the definite rectification effect was observed. Although the sensitivity of GdCoO3/MOx to ethanol was very low under dry conditions, it enhanced with the relative humidity (RH). The order of activity for GdCoO3/MOx element at RH 40% was ZnO>In2O3>Fe2O3.