Oxygen vacancy-enriched ALD NiO sub-50 nm thin films for enhanced triethylamine detection

Abstract

p-type metal oxide semiconductors have received significant interest in the field of gas sensors; however, it is quite challenging to achieve high sensor response because of inferior surface and electronic properties. Herein, we report a high-performance gas sensor fabricated by plasma-etching an NiO thin film deposited by atomic layer deposition. Ar plasma treatment is found to introduce a large number of oxygen vacancies, which effectively adjusts the electronic and chemical characteristics of the p-type NiO films to afford improved response to toxic triethylamine. The effects of the thickness of the sensing layer on sensor properties are also studied, which reveals that the NiO film with a thickness of 40 nm has the greatest gas sensing performance. After Ar plasma treatment, the response of the NiO thin films is significantly enhanced to enable an excellent limit of detection of 27.4 ppb, which is much lower than the threshold limit of 1 ppm proposed by American Conference of Governmental Industrial Hygienists. The demonstrated strategy and excellent sensor properties suggest a pathway to high performance gas sensors.