Low temperature solution-processed ZnO nanorod arrays with application to liquid ethanol sensors

Generation of oxygen vacancies in ZnO nanorods/films and their effects on gas sensing properties

“…Since Seiyama et al [4] discovered that the adsorption and desorption of gases produced rapid and remarkable changes in the electrical conductivities of semiconductors, several studies of the utility of semiconducting metal oxide materials as gas sensors have been reported [5][6][7][8]. ZnO is one of the most promising metal oxide materials for this purpose due to its thermal and chemical stability under standard operating environments, its high conductivity, and its non-toxic properties [8][9][10][11][12][13][14][15][16][17]. ZnO gas sensors have been intensively investigated recently, and films have been fabricated in a variety of structures, including as single crystals, thick/thin amorphous films, nanorod arrays, and nanotube assemblies [14][15][16][17].…”

“…Nanomaterials, especially one-dimensional (1D) nanostructures, provide good sensing properties because of their high surface-to-volume ratio (resulting from a high nanostructure aspect ratio), which facilitates the adsorption of oxygen groups and rapid transport of charge carriers. Many reports have attempted to improve the gas sensing properties of a device by introducing 1D nanostructures [8][9][10][11][12][13][14][15]. The effects of the nanostructures, however, are not yet fully understood because the gas sensing properties can vary with the crystal size, morphology, fabrication method, and applied processing steps.…”

Gallia–ZnO nanohybrid sensors with dramatically higher sensitivity to ethanol in presence of CO, methane and VOCs

“…The PL band is related to surface defect states and oxygen vacancies. By further M a n u s c r i p t 15 addition of gallia to the nanohybrid, the PL band intensity and the response to ethanol decrease, while the surface area slightly increases.…”

“…However, they suffer from some problems such as high working temperature, relative humidity dependence and long-term drift of the sensor response [9]. Among various MOSs, ZnO, widely known as a kind of wide-band gap semiconductor, is an excellent material for both oxidative and reductive gasses [11][12][13], due to their thermal/chemical stability, good oxidation resistibility, and advances in synthesis methods [14,15]. Also, ZnO is an interesting example of materials having the capability of low temperature growth with many different kinds of morphologies including wires, rods, tubes, particles and flower shape at nanoscale [16][17][18][19][20][21][22].…”

Fabrication of ZnO/CdS, ZnO/CdO core/shell nanorod arrays and investigation of their ethanol gas sensing properties

“…Among these 1D nanostructured metal oxides, ZnO is one of the most widely studied materials for gas sensors because it demonstrates thermal and chemical stability under standard operating environments, high conductivity and non-toxicity [1][2][3][4][5][6][7][8]. Recently, various types of approaches have been implemented to enhance the gas sensing properties of ZnO-based gas sensors: changing nanostructures [9][10][11][12][13], modifying surface defects [14,15], and employing other materials on the surface to create heterostructures [16][17][18][19].…”