Highly sensitive sensor of NH3 and ethanol vapours based on NiO/MPS heterojunction at room temperature

This article reports the low-cost fabrication of p-NiO/n-MPS heterostructure and its application for NH3 and C2H5OH sensing. Macroporous silicon (MPS) was synthesized by electrochemical anodization on an n-type Si surface, followed by the deposition of NiO by sol-gel dip-coating method. Aluminium electrical contacts for further measurements were deposited onto the structure NiO/MPS by evaporation technique under vacuum. Furthermore, the gas sensing performance for the detection of C2H5OH and NH3 at room temperature was investigated. The results indicated a high response of the sensor to NH3 and C2H5OH, the maximum response was found of 880 and 140%, respectively, for a concentration of 137 ppm. The investigation on response kinetics showed a fast response/recovery time of the sensor.