Peculiarities of Deposition Times on Gas Sensing Behaviour of Vanadium Oxide Thin Films

Abstract

The importance of vanadium oxide in solid state science as a semiconductor encouraged us to prepare and investigate its microstructure and surface properties related to gas sensing characteristics. Hence, vanadium oxide thin films were deposited by spray pyrolysis method. The prepared films were placed in an electric circuit and the sensing characteristics of these films to ethanol vapors were studied. It was possible to find correlations between nanostructure and electrical properties of the obtained thin films and to optimize conditions of its synthesis. By X-ray diffraction, field emission scanning electron microscopy, and atomic force microscopy, the structure of the deposited films was determined. Based on atomic force microscopy results, the fractal analysis showed a decreasing trend of the fractal dimension (the slope of the log (perimeter) vs. log (area)) versus the deposition time. It was found that the film growth and gas response were affected by the deposition time. The operating temperature of the sensor was optimized for the best gas response. In accordance with our findings, the film deposited at the lowest deposition time (20 min) had the highest sensing response to ethanol.

Growth and Characterization of Sputtered ZnO:ZnGa2O4 Dual-Phase Films on Sapphire Substrates for NO Gas-Sensing Applications

“…The root mean square and surface roughness ( R q ) were evaluated by considering the surface area of 3 μm × 3 μm from the AFM micrographs. The as-deposited ZnO:ZnGa 2 O 4 film exhibited the surface roughness of 9.34 nm, which was increased to 13.2 nm after annealing this film at 700 °C, indicating the favorable high surface roughness for gas-sensing sites to trap more NO molecules . The actual surface area of the films is larger than the projected surface area due to the presence of spherical grains.…”

“…The as-deposited ZnO:ZnGa 2 O 4 film exhibited the surface roughness of 9.34 nm, which was increased to 13.2 nm after annealing this film at 700 °C, indicating the favorable high surface roughness for gas-sensing sites to trap more NO molecules. 42 The actual surface area of the films is larger than the projected surface area due to the presence of spherical grains. The surface roughness of the ZnO:ZnGa 2 O 4 films decreased from 13.2 to 11.3 nm after annealing this film at 800 °C, as shown in Figure 4f, which can be attributed to the agglomeration of grains during annealing at a high temperature, indicating the difficulty in clearly distinguishing the grain boundaries.…”

Impact of some mineral-based nanoparticles versus carbon nanoallotropes on properties of liquid crystal hydroxypropyl cellulose nanocomposite films

“…The powder is indexed as phase pure orthorhombic V 2 O 5 , according to the standard data (Inorganic crystal structure database collection code-15984). The presence of a characteristic peak at 20.2° with panel (001) is evidence for the V 2 O 5 phase (Khatibani et al , 2016). MMT nanoclays diffractogram shows a characteristic peak at 2θ = 6.1° (001) with d-spacing 14.3° Å and other peaks 19.9° and 35.6° corresponding to (020) and (006) panels, respectively.…”

The effect of graphene and cobalt on ethanol sensing performance of ZnO based sensor prepared by sol-gel method

“…42) Variation of the adsorption/desorption of oxygen ions may be the reason for the temperature dependence of the sensing performance. 43) It seems each gas has various adsorption/desorption parameters which lead to forming a distinguished temperature profile. Enhancement of sensing performance arising from thermal treatment can be related to thermal energy.…”