Band gap measurements in thin films of hematite Fe2O3, pyrite FeS2 and troilite FeS prepared by chemical spray pyrolysis

Misho, R. H.; Murad, W.A.

doi:10.1016/0927-0248(92)90095-7

Cited by 66 publications

(27 citation statements)

References 10 publications

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“…This absorption behavior is characteristic of the ZnMn 2 O 4 spinel and is in agreement with previous reports [57,58,59]. In order to calculate the band gap energy, Tauc´s formula was used [60,61]. The bang gap energy was determined by extrapolating the linear part of the graph of (αhv) n versus hv up to energy axis at α = 0, where α is the optical absorption coefficient, and n = ½ for indirect transitions and = 2 for direct transitions (see inset of Figure 6).…”

Section: Resultssupporting

confidence: 84%

Synthesis of ZnMn2O4 Nanoparticles by a Microwave-Assisted Colloidal Method and their Evaluation as a Gas Sensor of Propane and Carbon Monoxide

Morán-Lázaro

Guillén-López

López–Urías

et al. 2018

Sensors

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Spinel-type ZnMn2O4 nanoparticles were synthesized via a simple and inexpensive microwave-assisted colloidal route. Structural studies by X-ray diffraction showed that a spinel crystal phase of ZnMn2O4 was obtained at a calcination temperature of 500 °C, which was confirmed by Raman and UV-vis characterizations. Spinel-type ZnMn2O4 nanoparticles with a size of 41 nm were identified by transmission electron microscopy. Pellet-type sensors were fabricated using ZnMn2O4 nanoparticles as sensing material. Sensing measurements were performed by exposing the sensor to different concentrations of propane or carbon monoxide at temperatures in the range from 100 to 300 °C. Measurements performed at an operating temperature of 300 °C revealed a good response to 500 ppm of propane and 300 ppm of carbon monoxide. Hence, ZnMn2O4 nanoparticles possess a promising potential in the gas sensors field.

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Section: Resultssupporting

confidence: 84%

Synthesis of ZnMn2O4 Nanoparticles by a Microwave-Assisted Colloidal Method and their Evaluation as a Gas Sensor of Propane and Carbon Monoxide

Morán-Lázaro

Guillén-López

López–Urías

et al. 2018

Sensors

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“…The extrapolation of region A leads to the intercept at 2.1080 eV and the extrapolation of region B leads to the intercept at 0.8990 eV. This result suggests that the Co 3 O 4 films have two direct allowed E g values depending upon the film thickness [7]. The analogous results are also reported for other oxides [7].…”

Section: Methodssupporting

confidence: 66%

“…This result suggests that the Co 3 O 4 films have two direct allowed E g values depending upon the film thickness [7]. The analogous results are also reported for other oxides [7]. Figure 5 gives the FTIR spectrum of CNP5 film.…”

Section: Methodssupporting

confidence: 65%

Synthesis and Optical Properties of Cobalt Oxide (Co[sub 3]O[sub 4]) Nanoclustered Films Produced by Pulsed DC Electrochemical Deposition Process

Shelke¹,

Khollam²,

Patil³

et al. 2011

AIP Conference Proceedings

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The Co 3 O 4 films were prepared using two steps method. Initially, the films were deposited on thoroughly cleaned copper substrates by using pulsed DC electrochemical deposition method from a solution containing Co (NO 3 ) 2 : 6H 2 O and H 3 BO 3 . The films were deposited at different molar concentrations: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 and 0.7 M of Co(NO 3 ) 2 in deposition bath. These as-deposited films were transformed into Co 3 O 4 phase by heating them at 400 o C/2hr. These as-heated films were characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, UVVisible spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. From the characterization studies, the as-heated films were found to be containing single cubic spinel Co 3 O 4 phase with high purity. The variation in molar concentration of Co(NO 3 ) 2 in deposition bath showed the intense effect on optical properties of Co 3 O 4 films. The better optical properties, absorptaQFH Į HPLWWDQFH İ ZHUH REWDLQHG Ior the Co 3 O 4 films prepared at 0.5 M concentration of Co(NO 3 ) 2 as compared to the data reported in literature. The strength and adhesion of as-heated films on copper substrate were found to be good for the molar concentrations of Co (NO 3 ) 2 < 0.6 M.

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“…(α E ph ) 0.5 is plotted as function of the photon energy E ph . Following a procedure used previously for Fe 2 O 3 films33, we determine E G as the energy at which the slope corresponding to the indirect bandgap absorption and the slope corresponding to the mid-gap states absorption intersect each other. We found E G = 2.13 eV for both 550 °C and 750 °C samples, corresponding to a photon wavelength of 583 nm.…”

Section: Resultsmentioning

confidence: 99%

Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

Wickman

Fanta

Burrows

et al. 2017

Sci Rep

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Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance.

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Band gap measurements in thin films of hematite Fe2O3, pyrite FeS2 and troilite FeS prepared by chemical spray pyrolysis

Cited by 66 publications

References 10 publications

Synthesis of ZnMn2O4 Nanoparticles by a Microwave-Assisted Colloidal Method and their Evaluation as a Gas Sensor of Propane and Carbon Monoxide

Synthesis of ZnMn2O4 Nanoparticles by a Microwave-Assisted Colloidal Method and their Evaluation as a Gas Sensor of Propane and Carbon Monoxide

Synthesis and Optical Properties of Cobalt Oxide (Co[sub 3]O[sub 4]) Nanoclustered Films Produced by Pulsed DC Electrochemical Deposition Process

Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

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