Synthesis of ZnO nanosheet arrays with exposed (100) facets for gas sensing applications.

ZnO nanosheet (NS) arrays have been synthesized by a facile ultrathin liquid layer electrodeposition method. The ion concentration and electrode potential play important roles in the formation of ZnO NS arrays. Studies on the structural information indicate that the NSs are exposed with (100) facets. The results of Raman and PL spectra indicate that there existed a large amount of oxygen vacancies in the NSs. The gas sensing performances of the ZnO NS arrays are investigated: the ZnO NS arrays exhibited high gas selectivity and quick response/recovery for detecting NO2 at a low working temperature. High binding energies between NO2 molecules and exposed ZnO(100) facets lead to large surface reconstructions, which is responsible for the intrinsic NO2 sensing properties. In addition, the highly exposed surface and a large amount of oxygen vacancies existing in the NSs also make a great contribution to the gas sensing performance.