Phase-dependent gas sensitivity of MoS chemical sensors investigated with phase-locked MoS.

In the present study, phase-dependent gas sensitivities of MoS chemical sensors were examined. While 1T-phase MoS (1T-MoS) has shown better chemical sensitivity than has 2H-phase MoS (2H-MoS), the instability of the 1T phase has been hindering applications of 1T-MoS as chemical sensors. Here, the chemical sensitivity of MoS locked in its 1T phase by using a ZnO phase lock was investigated. To develop MoS chemical sensors locked in the 1T phase, we synthesized a multi-dimensional nanomaterial by growing ZnO nanorods onto MoS nanosheets (ZnO@1T-MoS). Raman spectroscopy and x-ray photoelectron spectroscopy analyses of such phase-locked 1T-MoS subjected to flash light irradiation 100 times confirmed its robustness. ZnO nanomaterials hybridized on MoS nanosheets not only froze the MoS at its 1T phase, but also increased the active surface area for chemical sensing. The resulting hybridized material showed better response, namely better sensitivity, to NO gas exposure at room temperature than did 1T-MoS and 2H-MoS. This result indicated that increased surface area and heterojunction formation between MoS and ZnO constitute a more promising route for improving sensitivity than using the 1T phase itself.