Enhanced H2S sensing performance of BiFeO3 based MEMS gas sensor with corona poling

In this work, BiFeO3 (BFO) nanoparticles of rhombohedral distorted perovskite structure with a particle about 50–100 nm are prepared by a facile sol-gel method. The as-prepared BFO nanoparticles are treated by the corona poling under different electric fields. The H2S gas sensing performances of as-obtained BFO based MEMS sensors are improved with the increase of corona poling fields. The BFO-P4 (corona poling at 4 kV) sensor exhibites a high response value of 4.8 to 1.2 ppm H2S at 220 °C, with a detection limit of 10 ppb and a short response/recovery time of only 3/7 s respectively. The corona poling treatment promotes the ion displacement, lattice expansion and dipole moments increase with the enhanced internal electric field in BFO nanoparticles, which are responsible for the reduced band gap and the increased adsorption oxygen, and thus improving H2S sensing performances of BFO based Micro-Electro-Mechanical System (MEMS) gas sensor.