Structure and gas-sensing properties of SnO2-In2O3 nanocomposites synthesized by impregnation method

Plasma-induced sub-10 nm Au-SnO2-In2O3 heterostructures fabricated by atomic layer deposition for highly sensitive ethanol detection on ppm level

“…It has also been employed in modern different gas sensors [14][15][16]. In order to fabricate miniaturized and reliable SnO 2 -and In 2 O 3 -based hetero-structured SEs the following technological approaches have recently been proposed: sol-gel [17], solvothermal [18], microwave methods [19,20], spray pyrolysis [21], coaxial electrospinning [22], impregnation [23], hydrothermal deposition [24], ALD and PE-ALD [25][26][27][28][29], chemical vapor deposition (CVD) [30] and sputtering [31]. All these techniques can produce the SE crystalline size within the nm scale strengthening the influence of crystalline shape on the adsorption properties, which determine both gas sensitivity and selectivity.…”

Effect of Composition and Structure of Metal Oxide Composites Nanostructured on Their Conductive and Sensory Properties

“…The same phenomenon occurs as a result of the substitution of In 3+ in Sn 4+ and the formation of donor centers in the In 2 O 3 crystals upon the dissolution of SnO 2 in In 2 O 3 [35,47]. Note that in the X-ray diffractometry (XRD) spectra of the SnO 2 -In 2 O 3 composites, obtained by impregnation and containing from 5 to 20 wt % SnO 2 , only peaks related to nanoparticles and nanosized clusters of In 2 O 3 are observed.…”

“…It should be noted that both in the SnO 2 -Sb 2 O 5 system [48] and in the SnO 2 -In 2 O 3 system [35,47] observed at low concentrations of SnO 2 an increase in conductivity is accompanied by a decrease in the sensory response. This is due to a decrease in the concentration of oxygen vacancies, which serve as centers of oxygen chemisorption with the formation of active oxygen Оanions involved in sensory reactions [35,43,49,50].…”

“…As a result, ions are replaced in the lattice of particles with the formation of a corresponding solid solution, which ultimately can have a significant effect on the sensory properties of the composite. This is observed during the formation of composites during the codeposition of components from solutions containing a mixture of salts or organometallic precursors [14], as well as when crystals of one metal oxide are impregnated with a solution of a salt of another metal, followed by heat treatment of the impregnated samples [10,35].…”

“…The Sn 4+ ions dissolve in small amounts in In 2 O 3 crystals while expanding the In 2 O 3 lattice due to the appearance of an additional positive charge of the tin ion [35]. In this case, additional electrons, as in (1), are released and pass into the conduction band.…”