MoS2 hybrid heterostructure thin film decorated with CdTe quantum dots for room temperature NO2 gas sensor

Abstract

Molybdenum disulfide (MoS2) is a very promising candidate for room temperature (RT) gas sensing applications. However, the limitation of synthesis techniques, incomplete recovery, and selectivity at RT are prime drawbacks. In this report, MoS2 nanoworms (NWs) thin film and CdTe quantum dots (QDs) decorated MoS2 NWs hybrid heterostructure thin film (CdTe QDs/MoS2 NWs) have been fabricated by scalable sputtering technique on the p-Si substrate and tested for RT NO2 gas sensing applications. The proposed CdTe QDs/MoS2 NWs hybrid heterostructure thin film sensor manifests an excellent sensor response (∼40 %), fast response time = 16 s, complete recovery (recovery time = 114 s) and highly selective towards 10 ppm NO2 at room temperature in comparison to pristine MoS2 NWs thin film sensor (response ∼26 %, response/recovery time ∼23 s/incomplete recovery). This superior gas sensing performance may be attributed to the combined effect of factors such as hybrid heteronanostructure with unique morphology, catalytic activity, synergistic effects, and p-n heterojunctions. The approach employed here may lead to the development of RT operable MoS2-based heterojunction gas sensors.