Gas‐Sensing Properties of Spinodally Decomposed (Ti,Sn)O₂ Thin Films

Abstract

The gas-sensing properties of spinodally decomposed (Ti,Sn)O 2 thin films on sapphire substrates were investigated for CO, C 3 H 8 , and C 2 H 5 OH, and hydrogen gases at a temperature of 500°C. The variation in the d-spacing of the (101) plane of (Ti 0.5 Sn 0.5 )O 2 films showed behavior that was typical of spinodal decomposition during annealing at a temperature of 900°C. Transmission electron micrographs of the spinodally decomposed (Ti,Sn)O 2 films on sapphire (0112) substrates revealed the characteristic modulated structure. The modulated lamella microstructure consisted of TiO 2 -and SnO 2 -rich regions at intervals of ∼10 nm. The films were very sensitive to hydrogen gas and revealed anisotropic electrical conduction that was influenced by the modulated microstructure, which is characteristic of spinodal decomposition.

Self-Assembled Multilayer Structure and Enhanced Thermochromic Performance of Spinodally Decomposed TiO2–VO2 Thin Film

“…According to the lattice parameters of rutile TiO 2 ( a = 4.582, b = 2.953, PDF:78-1510) and tetragonal VO 2 ( a = 4.554, b = 2.8557, PDF:79-1655), the lattice mismatch in TVO system is 0.61% along a axis and 3.3% along c axis, and thus the modulation direction should be chosen as c axis direction to minimize the elastic strain energy at the interface. Similar phenomenon was observed in TiO 2 /SnO 2 system. , In this work, TVO thin film is deemed to share the same mechanism, and therefore the multilayer should be parallel to that of the a -axis of a-plane sapphire (11–20) substrates and tilted away from the interface based on the (101) orientation of the TVO thin films. A schematic diagram of the microstructure of the spinodally decomposed TVO thin film is showed in Figure .…”

Suppressing spinodal decomposition by incorporation of reduced graphene oxide into (Sn0.5Ti0.5)O2 solid solution

“…Nevertheless, further investigation should be warranted for more decisive and quantitative understanding of the spinodal decomposition mechanism in more various materials as well as in this system. Furthermore, this method for controlling microstructures through kinetics can be used as potential applications of material design for structural engineering and interface-critical devices such as gas sensors, catalysts, and varistors [8][9][10][11][12][13].…”

“…Both solid-solution and spinodally-decomposed phases in the SnO 2 -TiO 2 system have been used in various functional applications related to gas sensors, photocatalysts, and varistors [8][9][10][11][12][13]. For such practical applications, phase separation can be regarded occasionally as an adverse phenomenon to be avoided and suppressed.…”

Strain effects on spinodal decomposition in TiO2–VO2films on TiO2(100) substrates

“…There has been considerable interest in the spontaneous formation of multilayer films via nanoscale phase separation in oxide systems [1][2][3][4][5][6]. In particular, interest has been focused on vertical multilayer (VML) films in which the multilayer structures are aligned vertically on the surface of the substrate.…”