Theoretical study of alloys

Ding, Shoujun; Fan, Guanghan; Li, Shengtao; Chen, K.; Xiao, Bing

doi:10.1016/j.physb.2007.02.036

Cited by 50 publications

(28 citation statements)

References 21 publications

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“…However, the composition dependence does not allow comparison with the results presented here. Ding et al 36 reported theoretical investigation of the bandgap of ternary BeZnO with a bowing parameter of 5.6 eV. The bandgap bowing parameter b Eg_BeZnO has also been reported experimentally (4.5 eV in Ref.…”

Section: Resultsmentioning

confidence: 75%

Lattice parameters and electronic structure of BeMgZnO quaternary solid solutions: Experiment and theory

Toporkov

Demchenko

Zolnai

et al. 2016

Journal of Applied Physics

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BexMgyZn1−x−yO semiconductor solid solutions are attractive for UV optoelectronics and electronic devices owing to their wide bandgap and capability of lattice-matching to ZnO. In this work, a combined experimental and theoretical study of lattice parameters, bandgaps, and underlying electronic properties, such as changes in band edge wavefunctions in BexMgyZn1−x−yO thin films, is carried out. Theoretical ab initio calculations predicting structural and electronic properties for the whole compositional range of materials are compared with experimental measurements from samples grown by plasma assisted molecular beam epitaxy on (0001) sapphire substrates. The measured a and c lattice parameters for the quaternary alloys BexMgyZn1−x with x = 0−0.19 and y = 0–0.52 are within 1%–2% of those calculated using generalized gradient approximation to the density functional theory. Additionally, composition independent ternary BeZnO and MgZnO bowing parameters were determined for a and c lattice parameters and the bandgap. The electronic properties were calculated using exchange tuned Heyd-Scuseria-Ernzerhof hybrid functional. The measured optical bandgaps of the quaternary alloys are in good agreement with those predicted by the theory. Strong localization of band edge wavefunctions near oxygen atoms for BeMgZnO alloy in comparison to the bulk ZnO is consistent with large Be-related bandgap bowing of BeZnO and BeMgZnO (6.94 eV). The results in aggregate show that precise control over lattice parameters by tuning the quaternary composition would allow strain control in BexMgyZn1−x−yO/ZnO heterostructures with possibility to achieve both compressive and tensile strain, where the latter supports formation of two-dimensional electron gas at the interface.

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Section: Resultsmentioning

confidence: 75%

Lattice parameters and electronic structure of BeMgZnO quaternary solid solutions: Experiment and theory

Toporkov

Demchenko

Zolnai

et al. 2016

Journal of Applied Physics

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“…The band-gap energies based on Fig. 6 were compared with those of other references [5,[18][19][20][21]. As Fig.…”

Section: Methodsmentioning

confidence: 99%

Wide band-gap investigation of modulated BeZnO layers via photocurrent measurement

Kim

Yang

et al. 2012

J Mater Sci

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We grew modulated BeZnO layers by hybrid plasma-assisted molecular-beam epitaxy/electron-beam deposition. A wide band-gap investigation of the modulated Be x Zn 1-x O by means of photocurrent (PC) spectroscopy was conducted. The band-gap energy was directly acquired from the wavelength of the PC peak, caused by the band-to-band transition. By increasing x, which was the rate of the Be elements, the optical band-gap energy was empirically fitted by E BeZnO (x) = 6.32(x-1)x ? 7.305x ? 3.295. We expect that this finding can open new possibilities for wide band-gap engineering of BeZnO layers, which can be utilized as barrier layers in active layers consisting of ZnO/BeZnO quantum well structures and solar-blind ultraviolet photodetectors.

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“…We note that the Zn 3d electrons are explicitly included in the valence states. Previous DFT calculations on ZnXO (X=Cd, Mg, or Be) and GaZN (Z=Al or In) alloys 17,27,32,33,37,38 show that each supercell of the The atomic positions in the supercells were optimized until all components of the force on each atom were reduced to values below 0.02 eV/Å. The polarizations were calculated using the Berry-phase approach 39 where a reference phase with zero net polarization is needed.…”

Section: Methodsmentioning

confidence: 99%

“…The W structure and the primitive periodicity of the (0001) Previous DFT simulations assume that Zn 1-x Be x O solid solutions crystallize in the W structure for all x. 17,27 This is based on limited θ-2θ X-ray Diffraction (XRD) experiments on epitaxial or highly oriented Zn 1-x Be x O films grown on the (0001) α-Al 2 O 3 substrates. 16,25,31 XRD results show that the out-of-plane lattice parameter of Zn 1-x Be x O films varies linearly with increasing x.…”

Section: Crystal Structuresmentioning

confidence: 99%

“…16 Furthermore, since in Zn 1-x Be x O the band gap can theoretically be tuned from 3.37 to 10.60 eV, this materials system may replace Zn 1-x Mg x O solid solutions that are being considered in applications such as field effect transistors, polymer-oxide hybrid solar cells, quantum Hall effect devices, high-k films on Si, and acoustic resonators. [20][21][22][23][24] While there have been some efforts to understand, describe, and measure the lattice parameters, the band gap, and optical properties of Zn 1-x Be x O in thin films, 16,17,[25][26][27][28] the potential of this materials system for applications described above has not been fully explored. Of Dong show that depending on the composition, the alloys may have a different crystal structure than the end components ZnO and BeO.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical analysis of the crystal structure, band-gap energy, polarization, and piezoelectric properties of ZnO-BeO solid solutions

Alpay

2011

Phys. Rev. B

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The electrical properties, the spontaneous polarization, and the piezoelectric response of ZnO can be tailored by alloying ZnO with BeO for applications such as electrodes in flat panel displays and solar cells, blue and ultra-violet (UV) light emitting devices, and highly sensitive UV detectors. We present here the results of a study that employs density functional theory to analyze the crystal structure, the band structure, spontaneous polarization, and piezoelectric properties of

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Theoretical study of alloys

Cited by 50 publications

References 21 publications

Lattice parameters and electronic structure of BeMgZnO quaternary solid solutions: Experiment and theory

Lattice parameters and electronic structure of BeMgZnO quaternary solid solutions: Experiment and theory

Wide band-gap investigation of modulated BeZnO layers via photocurrent measurement

Theoretical analysis of the crystal structure, band-gap energy, polarization, and piezoelectric properties of ZnO-BeO solid solutions

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