MoS_2 oxygen sensor with gate voltage stress induced performance enhancement

摘要

Two-dimensional (2D) materials have recently attracted wide attention and rapidly established themselves in various applications. In particular, 2D materials are regarded as promising building blocks for gas sensors due to their high surface-to-volume ratio, ease in miniaturization, and flexibility in enabling wearable electronics. Compared with other 2D materials, MoS_2 is particularly intriguing because it has been widely researched and exhibits semiconducting behavior. Here, we have fabricated MoS_2 resistor based O_2 sensors with a back gate configuration on a 285 nm SiO_2/Si substrate. The effects of applying back gate voltage stress on O_2 sensing performance have been systematically investigated. With a positive gate voltage stress, the sensor response improves and the response is improved to 29.2% at O_2 partial pressure of 9.9 × 10~(-5) millibars with a+40 V back-gate bias compared to 21.2% at O_2 partial pressure of 1.4 × 10~(-4) millibars without back-gate bias; while under a negative gate voltage stress of -40 V, a fast and full recovery can be achieved at room temperature. In addition, a method in determining O_2 partial pressure with a detectability as low as 6.7 × 10~(-7) millibars at a constant vacuum pressure is presented and its potential as a vacuum gauge is briefly discussed.