Atomic layer deposited P-type nickel oxide and cobalt oxide for ethanol gas sensing

We present a comprehensive study of atomic layer deposited materials for ethanol gas sensing with large-scale fabrication techniques. Ultra-thin nickel oxide and cobalt oxide films show very promising performance in ethanol sensing. The films were measured at different temperatures and humidity levels. Unlike most semiconducting metal oxides used for gas sensing, nickel and cobalt oxide are p-type materials. The reactivity and sensitivity of p-type metal oxides offer their full potential only in thin compact form, where the highly resistive bulk does not dominate the current. Atomic layer deposition is an excellent method of fabrication for ultra-thin films and offers a versatile palette of potential semiconducting metal oxides materials for more target gases.