Synthesis of Nanograined ZnO Nanowires and Their Enhanced Gas Sensing Properties

Abstract

Polycrystalline ZnO nanowires with grain sizes ranging from 20 to 100 nm were synthesized using a newly designed two-step process: (first step) synthesis of ZnSe nanowires by vapor transportation of a mixture of ZnSe powders; and (second step) thermal oxidation of the ZnSe nanowires at 650 °C. Compared to the single-crystal ZnO nanowire gas sensors and other nanomaterial gas sensors reported previously, the multiple networked nanowire gas sensors fabricated from the nanograined ZnO nanowires showed substantially enhanced electrical responses to NO2 gas at 300 °C. The NO2 gas sensing properties of the nanograined ZnO nanowires increased dramatically with increasing NO2 concentration. The multiple-networked nanograined ZnO nanowire sensor showed a response value of 237,263% at 10 ppm NO2 and 300 °C, whereas the single-crystal ZnO nanowire sensors showed a response of only 6.5% under the same conditions. The recovery time of the nanograined ZnO nanowire sensor was much shorter than that of the normal ZnO nanowire sensor over the NO2 concentration range of 1-10 ppm, even though the response time of the former was somewhat longer than that of the latter. The origin of the enhanced NO2 gas sensing properties of the nanograined ZnO nanowire sensor is discussed.

Fabrication of a low-concentration H2S gas sensor using CuO nanorods decorated with Fe2O3 nanoparticles

“…For this reason, the sensitivity and selectivity of the CuO sensor material must be improved. Several methods to enhance the sensing properties of these materials are known, including forming core/shell structures [16], decoration with noble metals [17], structure modification [18], doping [19], and the decoration of the CuO surface with metal oxide semiconductor (MOS) nanoparticles [20]. Fe 2 O 3 , an n-type MOS, is also used for H 2 S gas sensing.…”

Facile Hydrothermal Synthesis of Hierarchical ZnO with Lignosulphonate and Its Photo Luminescence Property

“…Up to now, nanostructures of ZnO including prismatic, needle-like, ellipsoidal, tetra-pod-like, nanorod, nanofiber, nanobeltsand nanotubes have been prepared by various physical and chemical methods (Kim et al 2016, Park et al 2012.…”

UV-enhanced acetone gas sensing of Co3O4-decorated ZnS nanorod gas sensors

“…[7,8] The small cross-section of the 1D nanostructure sensor can lead to the complete depletion or accumulation of charge carriers in the bulk of the 1D nanostructure, resulting in a stronger response to the target gas. Moreover, the distance between the tunable conducting channel along the axis of the 1D nanostructure and the surface of the 1D nanostructure in contact with the gas is very small, leading to a short response time upon exposure to the target gas, as well as a significant increase in the sensitivity of the device due to the high surface-to-volume ratio of 1D nanostructures.…”