High sensitivity and low detection limit of acetone sensor based on NiO/Zn_2SnO_4 p-n heterojunction octahedrons

摘要

In this work, we successfully prepare the octahedral NiO/Zn_2SnO_4 p-n heterostructure by a simple hydrothermal synthesis and subsequent wet impregnation process. The microscopic morphology characterization results show that the as-prepared composites are uniformly dispersed and have an octahedral structure with a size of 3-5 μm. The gas devices are fabricated and their sensing performances are investigated systematically. The response and selectivity of NiO/Zn_2SnO_4 composites to acetone have been significantly improved than that of pure Zn_2SnO_4. Moreover, the response of the sensor to 100 ppb acetone is 1.4 at 300 °C, indicating that the detection limit is less than 100 ppb. The enhancement in sensing properties of composites is largely due to the p-n heterojunction formed by NiO and Zn_2SnO_4, which causes the transfer of carriers and the catalytic effect of NiO.