Epitaxial growth of corundum-structured wide band gap III-oxide semiconductor thin films

Fujita, Shizυo; Kaneko, Kentaro

doi:10.1016/j.jcrysgro.2014.02.032

Cited by 143 publications

(99 citation statements)

References 57 publications

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“…The band gap of the sprayed films is calculated using Tauc's relation using the following equation:

{(normalα normalh normalv)}^{2} = B true(h v - E g true)

where α , B , and Eg are the absorption coefficient, proportionality constant, and optical band gap; respectively, the absorption coefficient is calculated by the following equation:

α = 2.303 \frac{A}{t}

where A and t are the absorbance and thickness, respectively, Figure shows the band gap of pure and Ba‐doped Mn 3 O 4 thin films, the values fairly agree with the work reported in literature . It is found that band gap varies as Ba concentration increases reaching a minimum value 2.85 eV in Mn 3 O 4 :Ba1% thin films, the reduction in band gap may be due to the increase in RMS roughness and crystallite size as reported earlier, it is also observed band gap decreases with the increase in unit cell volume as well as bond lengths of (Mn 2+ O) and (Mn 3+ O) in tetrahedral and octahedral sites; respectively (see Table ) as Ba concentration increases, this behavior agrees with the findings reported in literature …”

Section: Resultssupporting

confidence: 54%

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Najim

Darwoysh

Dawood

et al. 2018

Physica Status Solidi (a)

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The fabrication of reliable and cost‐effective gas sensor for low concentrations of toxic gases such as ammonia is still a challenging task, in this work the authors report structural, topography, and optical properties of pure and Ba‐doped Mn3O4 thin films prepared by chemical spray pyrolysis (CSP) as well as its gas sensing performance toward low concentrations of ammonia gas. XRD analyses prove the films have tetragonal spinel structure with a preferred orientation along the direction (103). AFM and SEM measurements show the films have homogeneous with rough surfaces and porous structures. EDS measurement confirms the presence of Mn, O, and Ba elements according to a doping concentration ratio. Optical measurements show the optical band gap redshifts and the bond length expands as Ba concentration increases. The optimal results are achieved in Mn3O4:Ba1% thin films where porous structure, rough surface, high crystallinity, and maximum response toward (20, 30, 40, and 50 ppm) of ammonia gas with great stability. Empirical equations are suggested to evaluate the sensitivity in terms of relative bond length and RMS roughness. These results show the films are good candidates in p‐type MOS gas sensors.

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“…The band gap of the sprayed films is calculated using Tauc's relation using the following equation:

{(normalα normalh normalv)}^{2} = B true(h v - E g true)

where α , B , and Eg are the absorption coefficient, proportionality constant, and optical band gap; respectively, the absorption coefficient is calculated by the following equation:

α = 2.303 \frac{A}{t}

Section: Resultssupporting

confidence: 54%

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Najim

Darwoysh

Dawood

et al. 2018

Physica Status Solidi (a)

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“…5. The first one has a peak absorption at 368 nm which can be attributed to the transition of electrons from the valence band to the conduc- [42,43]. Addition of Fe ions shifted this peak to 376 nm.…”

Section: Optical Propertiesmentioning

confidence: 98%

Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

Cherifi

Chaouchi

Lorgoilloux

et al. 2016

PAC

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Fe-doped ZnO nanoparticles were synthesized by sol gel technique. Fine-scale and single phase hexagonal wurtzite structure in all samples were confirmed by SEM and XRD, respectively. The band gap energy depends on the amount of Fe and was found to be in the range of 3.11-2.53 eV. The electric and dielectric properties were investigated using complex impedance spectroscopy. AC conductivity data were correlated with the barrier hopping (CBH) model to evaluate the binding energy (W m ), the minimum hopping distance (R min ) and the density of states at Fermi level, N(E F ). Fe doping in ZnO also improved the photocatalytic activity. Thus, the sample Zn 0.95 Fe 0.05 O showed high degradation potential towards methylene blue (MB), i.e. it degrades 90% of BM in 90 min under UV light.

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“…The thermodynamically stable polymorph under standard conditions is the monoclinic  phase (space group 12, C2/m), which has consequently been the focus of most research efforts [7]. In the context of band gap engineering however, it has been suggested that rhombohedral -Ga2O3 (space group 167, R3 ̅ c) is desirable [8] since Al2O3 and In2O3 can both be found in isostructural polymorphs --Al2O3…”

Section: Introductionmentioning

confidence: 99%

α-Ga2O3 grown by low temperature atomic layer deposition on sapphire

Roberts

Jarman

Johnstone

et al. 2018

Journal of Crystal Growth

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-Ga2O3 is a metastable phase of Ga2O3 of interest for wide bandgap engineering since it is isostructural with -In2O3 and -Al2O3. -Ga2O3 is generally synthesised under high pressure (several GPa) or relatively high temperature (~500 o C). In this study, we report the growth of -Ga2O3 by low temperature atomic layer deposition (ALD) on sapphire substrate. The film was grown at a rate of 0.48 Å/cycle, and predominantly consists of -Ga2O3 in the form of (0001)-oriented columns originating from the interface with the substrate. Some inclusions were also present, typically at the tips of the -phase columns and most likely comprising -Ga2O3. The remainder of the Ga2O3 filmi.e. nearer the surface and between the -Ga2O3 columns, was amorphous. The film was found to be highly resistive, as is expected for undoped material. This study demonstrates that -Ga2O3 films can be grown by low temperature ALD and suggests the possibility of a new range of ultraviolet optoelectronic and power devices grown by ALD. The study also shows that scanning electron diffraction is a powerful technique to identify the different polymorphs of Ga2O3 present in multiphase samples.

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Epitaxial growth of corundum-structured wide band gap III-oxide semiconductor thin films

Cited by 143 publications

References 57 publications

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

α-Ga2O3 grown by low temperature atomic layer deposition on sapphire

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Epitaxial growth of corundum-structured wide band gap III-oxide semiconductor thin films

Cited by 143 publications

References 57 publications

Structural, Topography, and Optical Properties of Ba‐Doped Mn3O4 Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn3O4 Thin Films for Ammonia Gas Sensing Application

Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

α-Ga2O3 grown by low temperature atomic layer deposition on sapphire

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Product

Resources

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Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application