Effect of thermal annealing on the optical and structural properties of γ-Al2O3 films prepared on MgO substrates by MOCVD

Zhao, Li; Ma, Jin; Feng, Xianjin; Du, Xin; Wang, Weiguang; Wang, Mingxian

doi:10.1016/j.ceramint.2015.08.145

Cited by 11 publications

(4 citation statements)

References 40 publications

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“…First-principles calculations indicate that the actual optical band gap of γ-phase Al 2 O 3 film is much lower than the theoretical value [45,46]. Some researchers have reported the optical bandgap values of Al 2 O 3 films as 5.36 eV [47], 5.50-5.63 eV [48,49], and 5.80-5.89 eV [30], which is in good accordance with the results obtained in this work. As can be seen, the E g of the film decreases with the increase of the annealing temperature, which is consistent with the improvement of the structural properties of the film revealed in the XRD results.…”

Section: Resultssupporting

confidence: 90%

Study of the Annealing Effect on the γ-Phase Aluminum Oxide Films Prepared by the High-Vacuum MOCVD System

et al. 2021

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γ-phase aluminum oxide (γ-Al2O3) films are grown on MgO (100) wafers by metal organic chemical vapor deposition (MOCVD). Post-annealing process is conducted to study the influence of annealing temperature on the properties of the films. Structural analyses indicate that all the deposited and annealed films present a preferred growth orientation of γ-Al2O3 (220) along the MgO (200) direction. And the film annealed at 1100 °C exhibits the best film quality compared with those of the films grown and annealed at other temperatures. Scanning electron microscopy measurements also imply the best surface morphology for the γ-Al2O3 film annealed at 1100 °C, which is in good accordance with the structural analyses. Optical transmittance spectra show good transparency for all the deposited and annealed films in the visible wavelength region with an average transmittance value of 83.5%. The optical bandgaps are estimated to be in the range of 5.56–5.79 eV for the deposited and annealed films. Semiconductor films with high optical transmittance in the visible region as well as wide bandgaps are appropriate for the manufacture of transparent optoelectronic devices and ultraviolet optoelectronic devices.

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Section: Resultssupporting

confidence: 90%

Study of the Annealing Effect on the γ-Phase Aluminum Oxide Films Prepared by the High-Vacuum MOCVD System

et al. 2021

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“…The much superior stability of the Ag-2Mg-2Al specimen under electron bombardment, compared to the Ag-3Mg specimens, is probably due to the presence of Al 2 O 3 in the MgO film. Alumina is widely used due to its advantages of good thermostability, high mechanical strength, and high resistance to wear and corrosion, and it does not dissociate under bombardment by charged particles [27,39]. δ values of 2-9 for alumina are reported, depending upon the purity and microstructure of alumina [39].…”

Section: Secondary Electron Yield and Electron Bombardment Performancementioning

confidence: 99%

“…A systematic study of the SEE properties of MgO/Al 2 O 3 composite films has so far not been reported, and experiments are being conducted in this direction. Similar to MgO, alumina is an insulator with good physical and chemical properties, such as low electrical conductivity, high thermal conductivity, high SEE yields, wide bandgap, and thermodynamic and chemical stability [11,27]. In this study, Ag-Mg-Al alloy was prepared and properly activated in low oxygen pressure (P O2 ).…”

Section: Introductionmentioning

confidence: 99%

Surface Characterization and Secondary Electron Emission Properties of Alumina Containing MgO Film on Ag-Mg-Al Alloy

Zhou

Zhang

Wang

et al. 2018

Metals

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Ag-Mg alloy is used as a dynode material in electron multiplier tubes due to the high secondary electron yields (δ) of the surface of MgO film. However, MgO film is readily degraded under strong electron or ion bombardment, which results in a decrease in the lifetime of devices. In this study, alumina-containing MgO films of ~50–150 nm were developed on a Ag-2Mg-2Al alloy (silver alloy containing 2 wt % Mg and 2 wt % Al) after a thermal activation process performed at 500–600 °C under low oxygen pressures of 5.0–20.0 Pa. Auger electron spectroscopy and X-ray photoelectron spectroscopy analyses reveal that the film consists of a thin layer of pure MgO and a relatively thicker layer of alumina-containing MgO located beneath the top MgO layer. The alumina-containing MgO film exhibits high δ value of 7.7 at a primary electron energy of 580 eV and a much better stability under energetic electron bombardment than pure MgO film on Ag-Mg alloy. Alumina has higher bond dissociation energy than MgO, and the presence of alumina in the film contributes to mitigating the dissociation of the MgO film under electron bombardment. The Ag-2Mg-2Al alloy with alumina-containing MgO film is a promising candidate as a dynode material for electron multiplier tubes.

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“…Several techniques have been demonstrated to fabricate CMT thin films such as magnetron sputtering [4], pulsed laser deposition [5], sol-gel process [6,7] and metal-organic chemical vapor deposition [8]. Among those methods, aqueous solution-gel technology is advantageous over other technologies in terms of low temperature preparation, low cost, environmental benignity and precise control of the chemical composition of thin films, making it a very promising method to produce homogeneous thin films.…”

Section: Introductionmentioning

confidence: 99%

Ca(Mg1/3Ta2/3)O3 dielectric thin films: preparation, structure, mechanical and dielectric properties

Zhou

Chen

et al. 2016

J Mater Sci: Mater Electron

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The effect of annealing temperature on the crystallinity, grain size and hence mechanical and dielectric properties of Ca(Mg 1/3 Ta 2/3 )O 3 (CMT) dielectric films were systematically studied. The CMT thin films were fabricated by an aqueous solution-gel technology and exhibited uniform, smooth and dense morphologies. The optimum pyrolysis temperature and time was 550 o C and 330 s. All the CMT films show a single perovskite phase and the crystallization increases with annealing temperature. The hardness and reduced modulus were effectively enhanced by increasing the annealing temperature, which can be correlated to the crystallinity and densification improvements.Higher elastic recovery was observed for CMT films annealed at higher temperatures indicating less difficult recoveries for those films. We also noticed that the dielectric constants were improved for the samples annealed at higher temperature, which may enable higher performances for future microwave communication electronics.

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Effect of thermal annealing on the optical and structural properties of γ-Al2O3 films prepared on MgO substrates by MOCVD

Cited by 11 publications

References 40 publications

Study of the Annealing Effect on the γ-Phase Aluminum Oxide Films Prepared by the High-Vacuum MOCVD System

Study of the Annealing Effect on the γ-Phase Aluminum Oxide Films Prepared by the High-Vacuum MOCVD System

Surface Characterization and Secondary Electron Emission Properties of Alumina Containing MgO Film on Ag-Mg-Al Alloy

Ca(Mg1/3Ta2/3)O3 dielectric thin films: preparation, structure, mechanical and dielectric properties

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