Sharply-precipitated spherical assembly of ZnO nanosheets for low temperature H2S gas sensing performances

We report the room-temperature preparation of ZnO nanostructures and their gas sensing properties. Nanosheet-constructed ZnO spheres were chemically precipitated in a surfactant-free alkaline solution in just a few minutes. X-ray diffraction and Raman spectra confirm the wurtzite structure of ZnO. Electron microscopy observations reveal the nanosheets having {101¯0} facets are grown in the [0001] direction. The nanosheets are formed as a result of the lateral oriented attachment of paralleled nanorods through edge sharing. The electronic band gap of ZnO is determined to be 3.37 eV from the band edge optical absorption. An intense yellow emission at 595 nm appears in the photoluminescence spectra, implying that the solution-grown ZnO is rich in oxygen. The ZnO architectures display linear sensitivity, good selectivity and repeatability for the sensing of 5–100 ppm H2S at 70 °C. The superior H2S sensing properties of the ZnO nanostructures are ascribed to their ultrathin building blocks of nanosheets.
Source: Materials Science in Semiconductor Processing - Category: Materials Science Source Type: research