Single ultrathin WO3 nanowire as a superior gas sensor for SO2 and H2S: Selective adsorption and distinct I-V response.

In order to take insight into the gas sensing performance of single ultrathin WO 3 nanowire, we performed first principles calculation to investigate the gas adsorption properties and used non-equilibrium Green function (NEGF) to investigate the electron transport properties of WO 3 nanowires with gas adsorption. Our investigation indicated that the WO 3 nanowires with/without oxygen vacancies are both sensitive to H 2 S due to the large adsorption energies and distinct charge transfer. Besides, we found that the WO 3 nanowire with O a type oxygen vacancies is highly selective to SO 2. We supposed that the high chemical activity and the small molecular volume of H 2 S and SO 2 are the main reasons of the selectivity. Finally, the negative differential resistance (NDR) effect of single ultrathin WO 3 nanowire and the gate voltage were proposed to benefit the application of WO 3 nanowires gas sensors. We also supposed two ways to take advantage of the NDR effect of single ultrathin WO 3 nanowire in gas sensing applications. It should be noted that this is the first theoretical investigation of WO 3 nanowires gas sensors considering the electron transport properties. Our work highlighted the possibility to use the single ultrathin WO 3 nanowire as superior gas sensors for SO 2 and H 2 S. Image 1 • The single ultrathin WO 3 nanowire without oxygen vacancies was sensitive to H 2 S. • The single ultrathin WO 3 nanowire with oxygen vacancies was sensitive to SO 2. • High chemical activity and small molecular volume are main reasons of selectivity. • Negative differential resistance effect will benefit gas sensing application. [ABSTRACT FROM AUTHOR]