Abstract:Microstructural properties of Ce 1−x Gd x O 2−δ (x = 0 to 0.3) thin films prepared by pulsed laser deposition technique were studied. The thin films were deposited on Si(100) substrate at a substrate temperature of 973 K at the oxygen partial pressure of 0.2 Pa using KrF excimer laser with energy of 220 mJ. The prepared thin films were characterized by X-ray diffraction, Raman spectroscopy and atomic force microscopy. X-ray diffraction analysis confirmed the polycrystalline nature of the thin films. Crystallit… Show more
“…The dislocation density (δ) is defined as the length of dislocation lines per unit volume of the crystal and was determined using the following relation , …”
Section: Resultsmentioning
confidence: 99%
“…where "θ" is the diffraction angle, "β" is full width at half maxima, and "λ" is the monochromatic X-ray wavelength. The dislocation density (δ) is defined as the length of dislocation lines per unit volume of the crystal and was determined using the following relation 23,24 Dislocation density is decreased with increasing substrate temperature, as the dislocation density indicates the dislocation network in the indium oxide thin films. The reduction in dislocation density reflects the emergence of good-quality thin films at higher deposition temperatures.…”
Toluene gas is the most toxic and affects the respiratory system of humans, and thereby, its detection at lower levels is an important task. Herein, we report a room temperature-operatable indium oxide-based chemiresistive gas sensor, which detects 50 ppm toluene vapors. Nanocrystalline indium oxide (In 2 O 3 ) films were sprayed on a precleaned glass substrate using a cost-effective spray pyrolysis method at different substrate temperatures in the range of 350−500 °C. The X-ray diffraction studies confirmed that the sprayed thin films, which were deposited at different substrate temperatures, exhibit a cubic structure. The preferred orientation was aligned along the (222) orientation. Average crystallite size calculation based on the Scherrer formula indicates that the crystallite size increases with the enhancement of substrate temperature. FESEM analysis showed that the indium oxide thin films possess uniform grain distribution, which persists over the entire substrate. As the substrate temperature is increased, a partial agglomeration in the film morphology was observed. The deposited film's nanostructured nature was confirmed by transmission electron microscopy, and the polycrystalline nature was confirmed from the selected area electron diffraction pattern. Root mean square roughness of the samples was determined from the atomic force microscopy studies. From the Raman spectra, characteristic vibrational modes appeared at 558.61, 802.85, and 1097.18 cm −1 in all the samples, which confirms the cubic structure of indium oxide thin films. Photoluminescence emission spectra have been recorded with an excitation wavelength of 280 nm. The optical band gap was measured using the Tauc plot. The band gap was found to decrease with an increase in the substrate temperature. The gas-sensing performance of indium oxide films sprayed at various substrate temperatures has demonstrated a better response toward 50 ppm toluene gas at room temperature with good stability, and the response and recovery times were determined using a transient response curve.
“…The dislocation density (δ) is defined as the length of dislocation lines per unit volume of the crystal and was determined using the following relation , …”
Section: Resultsmentioning
confidence: 99%
“…where "θ" is the diffraction angle, "β" is full width at half maxima, and "λ" is the monochromatic X-ray wavelength. The dislocation density (δ) is defined as the length of dislocation lines per unit volume of the crystal and was determined using the following relation 23,24 Dislocation density is decreased with increasing substrate temperature, as the dislocation density indicates the dislocation network in the indium oxide thin films. The reduction in dislocation density reflects the emergence of good-quality thin films at higher deposition temperatures.…”
Toluene gas is the most toxic and affects the respiratory system of humans, and thereby, its detection at lower levels is an important task. Herein, we report a room temperature-operatable indium oxide-based chemiresistive gas sensor, which detects 50 ppm toluene vapors. Nanocrystalline indium oxide (In 2 O 3 ) films were sprayed on a precleaned glass substrate using a cost-effective spray pyrolysis method at different substrate temperatures in the range of 350−500 °C. The X-ray diffraction studies confirmed that the sprayed thin films, which were deposited at different substrate temperatures, exhibit a cubic structure. The preferred orientation was aligned along the (222) orientation. Average crystallite size calculation based on the Scherrer formula indicates that the crystallite size increases with the enhancement of substrate temperature. FESEM analysis showed that the indium oxide thin films possess uniform grain distribution, which persists over the entire substrate. As the substrate temperature is increased, a partial agglomeration in the film morphology was observed. The deposited film's nanostructured nature was confirmed by transmission electron microscopy, and the polycrystalline nature was confirmed from the selected area electron diffraction pattern. Root mean square roughness of the samples was determined from the atomic force microscopy studies. From the Raman spectra, characteristic vibrational modes appeared at 558.61, 802.85, and 1097.18 cm −1 in all the samples, which confirms the cubic structure of indium oxide thin films. Photoluminescence emission spectra have been recorded with an excitation wavelength of 280 nm. The optical band gap was measured using the Tauc plot. The band gap was found to decrease with an increase in the substrate temperature. The gas-sensing performance of indium oxide films sprayed at various substrate temperatures has demonstrated a better response toward 50 ppm toluene gas at room temperature with good stability, and the response and recovery times were determined using a transient response curve.
“…S1. The average mean grain size (MGS) of the NCs was calculated by the Debye- Scherer equation as follows 58,59 :where β is the broadening in the full-width at half maximum (FWHM), λ is the X-ray wavelength (1.5406 Å), and θ is the Bragg diffraction angle. The microstrain, ε , of the NCs is evaluated byFigure 3XRD spectra of the cerium oxide nanocubes (CeO 2 NCs) as a function of urea concentrations.…”
This study describes a simple, high-yield, rapid, and inexpensive route for the synthesis of cubic shape-like cerium oxide nanocubes (CeO2 NCs) using different urea concentrations (0.5, 1.0, and 2.0 g) by the hydrothermal method. The synthesized nanocubes (NCs) are labeled as CeO2 NCs-0.5, CeO2 NCs-1.0, and CeO2 NCs-2.0, corresponding to 0.5, 1.0, and 2.0 g of urea, respectively. The synthesized NCs were characterized by FT-IR, UV-visible, XRD, XPS, SEM and HR-TEM analysis. The synthesized NCs were cubic in shape with average sizes of 12, 12, and 13 nm for the CeO2 NCs-0.5, CeO2 NCs-1.0, and CeO2 NCs-2.0, respectively, obtained by the XRD analysis. The catalytic activity of the CeO2 NCs was studied for the purpose of obtaining the reduction of malachite green (MG) in the presence of sodium borohydride (NaBH4) at room temperature.
“…10 mol% Gd doped ceria powder was prepared by sol-gel method with commercially available cerium ammonium nitrate [Ce(NH 4 ) 2 (NO 3 ) 6 ] and gadolinium nitrate [Gd(NO 3 ) 3 ], having 99.99% purity were used as starting precursors. Synthesis process of 10 mol% Gd doped ceria powder by sol gel process was reported elsewhere [22]. The sol gel prepared Gd doped ceria powder has made into pellets with 20 mm diameter and 5 mm thickness at a pressure of 3 tons/cm 2 by using a hydraulic pelletizer.…”
Section: Methodsmentioning
confidence: 99%
“…Dislocation density ı = 1 (crystallite size) It is observed that the dislocation density and strain are found to decrease with increase of oxygen partial pressure. It is due to large number of collisions of ablated atoms that have a higher probability to agglomerate before reaching the substrate [22]. The variation of strain (ε) and dislocation density (ı) with oxygen partial pressures of the Gd doped ceria thin films are tabulated in Table 1.…”
Microstructural properties of 10 mol% gadolinium doped ceria (CeO 2) thin films that were deposited on quartz substrate at substrate temperature of 1023 K by using pulsed laser deposition with different oxygen partial pressures in the range of 50-200 mTorr. The influence of oxygen partial pressure on microstructural, morphological, optical and gas sensing characterization of the thin films was systematically studied. The microstructure of the thin films was investigated using X-ray diffraction, atomic force microscopy and Raman spectroscopy. Morphological studies have been carried out using scanning electron microscope. The experimental results confirmed that the films were polycrystalline in nature with cubic fluorite structure. Optical properties of the thin films were examined using UV-vis spectrophotometer. The optical band gap calculated from Tauc's relation. Gas sensing characterization has been carried at different operating temperatures (room temperature to 523 K) for acetone gas. Response and recovery times of the sensor were calculated using transient response plot.
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