| 초록 |
Transition metal dichalcogenides (TMDCs, MX2: M = Mo, W; X = S, Se) have attracted significant attention as a promising two-dimensional (2-D) nanomaterial for advanced devices due to their remarkable electronic and optical properties as well as chemical stability. Furthermore, recently the 2-D TMDCs have shown the potential as a gas sensing material due to their very high surface-to-volume ratio, semiconducting property, and low power consumption. Thus, the MoS2 that is the one of the most popular TMDCs has been studied for its gas sensing properties and demonstrated an excellent response to various gas molecules, such as nitrogen dioxide (NO2), ammonia (NH3), triethylamine, tetrahydrofuran, acetone. Since the high potential for TMDCs gas sensor application, the improvement of gas-sensing performance such as high response and selectivity is actively studied. For example, the enhanced response of gas sensor can be achieved by the field effect transistor (FET) gas sensor and the vertically aligned MoS2 gas sensor, while a mercaptoundecanoic acid functionalized MoS2 gas sensor shows selective response toward different VOCs. However, these recent works did not show good recovery for gas sensor and were inadequate for repetitive use. Thus, another approach to satisfy a good recovery is required for repeatable 2D TMDCs gas sensor. Here, we demonstrate the improvement of gas-sensing performance of large-area tungsten disulfide (WS2) nanosheets through surface functionalization using Ag nanowires (NWs). Large-area WS2 nanosheets were synthesized through atomic layer deposition of WO3 followed by sulfurization. The pristine WS2 gas sensors exhibited a significant response to acetone and NO2 but an incomplete recovery in the case of NO2 sensing. After AgNW functionalization, the WS2 gas sensor showed dramatically improved response (667%) and recovery upon NO2 exposure. Our results establish that the proposed method is a promising strategy to improve 2D TMDC gas sensors. |
