Structural Characterization of Sr Doped LaFeO3 Thin Films Prepared By Pulsed Electron Deposition Method (original) (raw)
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The Effect of Strontium Doping on LaFeO3 Thin Films Deposited by the PLD Method
Catalysts
The aim of the presented investigations was to deposit the thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) on (100) Si substrate by using the Pulsed Laser Deposition (PLD) method. Structure was exanimated by using XRD, SEM, AFM, TEM and XPS methods. The catalytic properties were analyzed in 4 ppm acetone atmosphere. The doping of Sr thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) resulted in a decrease in the size of the crystallites, the volume of the elemental cell and change in the grain morphology. In the LaFeO3 and La0.9Sr0.1FeO3, clusters around which small grains grow are visible in the structure, while in the layer La0.8Sr0.2FeO3, the visible grains are elongated. The TEM analysis has shown that the obtained thin films had a thickness in the range 150–170 nm with triangular or flat column ends. The experiment performed in the presence of gases allowed us to conclude that the surfaces (101/020) in the triangle-shaped columns and the plane (121/200) faces in flat columns were exposed to g...
ACS applied materials & interfaces, 2014
In the present work, perovskite LaFeO3 thin films with unique morphology were obtained on silicon substrate using radio frequency magnetron sputtering technique. The effect of thickness and temperature on the morphological and structural properties of LaFeO3 films was systematically studied. The X-ray diffraction pattern explored the highly oriented orthorhombic perovskite phase of the prepared thin films along [121]. Electron micrograph images exposed the network and nanocube surface morphology of LaFeO3 thin films with average sizes of ∼90 and 70 nm, respectively. The developed LaFeO3 thin films not only possess unique morphology, but also influence the gas-sensing performance toward NO2. Among the two morphologies, nanocubes exhibited high sensitivity, good selectivity, fast response-recovery time, and excellent repeatability for 1 ppm level of NO2 gas at room temperature. The response time for nanocubes was 24-11 s with a recovery duration of 35-15 s less than the network struct...
Jurnal Penelitian Fisika dan Aplikasinya (JPFA)
The acetone gas sensor is one type of sensor being researched for its application because it detects the presence of diabetes in sufferers. Gas sensors with high sensitivity and low operating temperature have been extensively investigated for this purpose, and this research is focused on the same purpose. Synthetization and characterization of LaFeO3 with co-doping Gd2O3 and CoO thick film ceramics for acetone gas sensor was conducted. LaFeO3 was made using the co-precipitation method with 2.5% CoO for each and 0%, 2.5%, and 5% Gd2O3 variation to the LaFeO3. The LaFeO3 thick film was prepared using the screen-printing technique and calcined at 800°C for two hours. The analysis of crystal structure characterization using X-Ray Diffraction (XRD) resulted in LaFeO3 with co-doping Gd2O3 and CoO thick film ceramics having the same cubic crystal phase with smaller lattice parameters and crystallite sizes after doping were added. The results of morphology structure characterization using S...
2019
Nowadays, semiconductor is one of the most important materials in the application of science and technology, especially gas sensor. In this present work, characterization of undoped and doped 10 mol% SrO on LaFeO3 based ethanol gas sensors has been conducted using LaCl3.7H2O, Fe2O3 from yarosite extraction, and SrCl2.6H2O. The used materials were prepared through coprecipitation method. The ethanol gas sensors were made in the form of the thick film using screen printing techniques and fired at 600°C for 2 hours. Characterization of crystal and morphology structures was carried out using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. Electrical properties of ethanol gas sensors were examined using a gas chamber. The XRD analysis indicated that thick films had a cubic crystal structure. The SEM analysis showed that doped 10 mol% SrO decreased the grain size of LaFeO3 from 31.29 nm to 29.56 nm. The analysis of electrical properties showed that the thick ...
2019
Preparation and characterization of Al2O3-dopped LaFeO3 thick film ceramics for ethanol gas sensor applications has been conducted. LaFeO3 ceramics were made by co-precipitation method with doping variation of Al2O3 0% and 3.75% mole of the main ingredients LaFeO3 (La2O3 and Fe2O3). Screen printing technique was employed to make thick film ceramics of LaFeO3 and Al2O3-dopped LaFeO3. The ceramics were calcined at temperature of 60 0C. The analysis results of the characteristics of crystals using X-Ray Difraction (XRD) showed that the made ceramics made had cubic phase with a lattice parameter a=b=c=39.52nm. The addition of 3.75% mole of Al2O3 did not change the crystal phase and lattice parameter values of LaFeO3. The crystallite size of LaFeO3 was 52.17nm while the crystallite size of Al2O3-doped LaFeO3 was 44.52nm. The analysis results of morphological structure ceramics of LaFeO3 and Al2O3-doped LaFeO3 using Scanning Electron Microscopy (SEM) possessed a grain size of each 0:40 μm...
Material Science Research India, 2020
In this investigation we are reporting the rapid preparation of Perovskite LaFeO3 thin films prepared by sol-gel synthesis followed by spin coating method. The structural properties of the spin coated LaFeO3 thin films measured by X-ray Diffractometer which confirms the formation of monophasic, orthorhombic, Perovskite LaFeO3 material. The morphological features of the films were explore by the ease of scanning electron microscopy, where the crystalline LaFeO3 nanoparticles were observed. Energy dispersive spectroscopy was utilized for the determination of elemental composition. The electrical properties were carried out to confirm the typical semiconducting behaviour of LaFeO3 p- type semiconductor. The thin films were subjected for gas sensing study, the material was found to be very efficient gas sensors for LPG, petrol vapour, CO2, methanol, ethanol, acetone gases. The main object was to discuss comparative study, means, what changes in parameters may be observed due to doping e...
Sensors and Actuators B: Chemical, 2021
A comparative study of La 1-x Ca x FeO 3 (0.4 ≤ x ≤ 0.8) pellets and La 0.6 Ca 0.4 FeO 3 thin films for the selective detection of low concentration SO 2 gas has been performed. The La 0.6 Ca 0.4 FeO 3 thin films exhibited superior gas sensing performance than La 1-x Ca x FeO 3 (0.4 ≤ x ≤ 0.8) pellets in terms of sensitivity, operating temperature, detection limit, response, and recovery time. The HRTEM images confirm the nanoparticle nature of the La 1x Ca x FeO 3 (0.4 ≤ x ≤ 0.8) samples. The material crystallizes in the orthorhombic crystal system with the Pbnm space group. Further, occupancy refinement of neutron diffraction data indicates the presence of oxygen vacancies which was also supported by XPS analysis. Among the various compositions of La 1-x Ca x FeO 3 (0.4 ≤ x ≤ 0.8), the x = 0.4(La 0.6 Ca 0.4 FeO 3) was found to exhibit the best gas sensing performance and chosen for thin film preparation. The gas sensing studies of thin films, prepared by the DC magnetron sputtering method, confirm the enhanced gas sensitivity towards 3 ppm SO 2 gas at a low operating temperature of 120 • C. The selectivity studies show that La 1-x Ca x FeO 3 (0.4 ≤ x ≤ 0.8) preferentially detects SO 2 gas at the given operating condition over other gases such as CH 4 , CO 2 , and CO. The gas sensing mechanism and high sensitivity of the La 1-x Ca x FeO 3 sensor towards the detection of SO 2 gas were explained by DFT calculations which give evidence for the strong binding of SO 2 molecules on the 121 surface of the sensor.
Characteristics of a thick film ethanol gas sensor made of mechanically treated LaFeO3 powder
In this work, fabrication of LaFeO 3 thick film ceramics for ethanol gas sensor made of mechanically treated (milling) powder was studied. The thick films were fabricated using screen printing technique from LaFeO 3 powder treated by HEM (High Energy Milling). The films were baked at 800 o C for one hour and analyzed using XRD and SEM. Sensitivity of the films was studied by measuring resistance of them at various temperatures in a chamber containing air with and without ethanol gas. Data of XRD showed that the thick film crystalizes in orthorombic structure with space group of Pn*a. SEM data showed that the films consisted of small grains with grain size of about 225 nm. According to the electrical data, the LaFeO 3 thick films that produced in this work could be applied as ethanol gas with operating temperature of about 275 o C.
Effect of precursors on the morphology and surface area of LaFeO3
Ceramics International, 2019
Surface area and morphology of materials play an important role on their gas sensing performance because of the varying number and nature of adsorption sites. Current work reports a comparative study of LaFeO 3 synthesized by the facile hydrothermal method using two precursors; citric acid and KOH. The microstructure observed through FESEM and TEM showed different morphologies for the two precursors and calcination time (2 h & 6 h). Prior to calcination, higher surface area (50.54 m 2 /g) was obtained for LaFeO 3 prepared using KOH as compared to that for LaFeO 3 using citric acid (3.21 m 2 /g). Surface area increased from 3.21 to 7.06 m 2 /g for citric acid and decreased from 50.54 to 11.42 m 2 /g for KOH as calcination takes place for 6 h. Needle-shaped morphology of p-type LaFeO 3 with high surface area (50.54m 2 /g) for KOH would provide large active sites which would enhance sensitivity towards gases. Hence, LaFeO 3 samples prepared using KOH with and without calcination are expected to give better performance for gas sensing than LaFeO 3 samples synthesized using citric acid.
Sensors and Actuators B: Chemical, 2001
Pure and Sn-doped a-Fe 2 O 3 thin ®lms were deposited on Al 2 O 3 substrate by plasma enhanced chemical vapor deposition (PECVD) process using Fe(CO) 5 and SnCl 4 as a source materials. The a-Fe 2 O 3 phase was most stable in the deposition temperature range from 80 to 1208C and exhibited a relatively high sensitivity to i-C 4 H 10 and CO. On the other hand, a-Fe 2 O 3 thin ®lm was almost insensitive to CH 4 regardless of heat treatment and gas concentration. This paper describes the fabrication procedure and its sensing characteristics are presented. Particularly, the sensing characteristics of pure a-Fe 2 O 3 and Sn doped a-Fe 2 O 3 have been compared.