Hybrid density functional study of band alignment in ZnO–GaN and ZnO–(Ga1−xZnx)(N1−xOx)–GaN heterostructures

Wang, Zhenhai; Zhao, Mingwen; Wang, Xiaopeng; Yan, Xi; He, Xiujie; Liu, Xiangdong; Shen, Yan

doi:10.1039/c2cp42115a

Cited by 47 publications

(36 citation statements)

References 36 publications

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“…It can also be seen in Table III that the strain contribution is positive in all cases. Wang et al 9 found that the dipole contribution is almost independent of the functional used. This supports our approach of calculating the dipole at the LDA level, while the individual band edges in each material require the use of the GW corrections.…”

Section: Discussionmentioning

confidence: 99%

“…Since these band-offsets also depend strongly on strain, a detailed comparison be-tween different results requires considering which strain state was assumed. For example, the results of Wang et al 9 correspond to a coherently strained interface. Since in strained GaN, the VBM is split, it increases the valence band offset.…”

Section: Discussionmentioning

confidence: 99%

“…They in addition studied core-shell nanowire heterostructures. Wang et al 9 find valence band offsets ranging from 0.455 eV to 1.588 eV depending on which exchange correlation functional is used. Using GGA functionals PBE or PW91 they find relatively small offsets while adding Hubbard U for the Zn-3d and Ga-3d, the band offset is increased.…”

Section: Discussionmentioning

confidence: 99%

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Band offsets between ZnGeN2, GaN, ZnO, and ZnSnN2and their potential impact for solar cells

Punya

Lambrecht

2013

Phys. Rev. B

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The band offsets between the Zn-IV-N2 nitrides, ZnGeN2 and ZnSnN2, and two other closely lattice matched semiconductors, ZnO and GaN, are calculated using density functional theory calculations including quasiparticle corrections. The interface dependence as well as the role of strain are investigated. A staggered type-II alignment is found between ZnGeN2, GaN and ZnO with ZnO having the lower and ZnGeN2 having the higher valence band maximum. The potential benefits of this alignment for photovoltaic applications is pointed out.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Band offsets between ZnGeN2, GaN, ZnO, and ZnSnN2and their potential impact for solar cells

Punya

Lambrecht

2013

Phys. Rev. B

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“…In this work, we evaluate both VB and CB offsets directly by the potential-line-up method [33][34][35] to provide an energy band alignment for α − β mixed-phase Ga 2 O 3 . Furthermore, the effect of the bonding network near the interface on the band offsets with the charge depletion layer is addressed, which is particular useful to determine the size of catalyst particles because the sizes should be essentially less than or equal to twice the width of the space charge region for the full extent of band bending.…”

Section: Introductionmentioning

confidence: 99%

Tuning the energy band-gap of crystalline gallium oxide to enhance photocatalytic water splitting: mixed-phase junctions

Wang

Liang

et al. 2014

J. Mater. Chem. A

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Rational design and fabrication of mixed-phase oxide junctions is an attractive strategy in the photocatalytic applications. A new tuneable α-β mixed-phase Ga2O3 has recently been discovered to have the high activity in the photocatalytic water splitting. Here we perform a first-principles study to reveal the nature of efficient separation of photogenerated carriers achieved by the mixed-phase Ga2O3. It is found that the tensile strain and lattice misfitting at the interface junctions significantly tune their energy bands. As the interior angles between two components change, the characteristics of valence band-edge states can be significantly different. Through the analysis on the bonding strength of the bonds near the interfaces, and the comparison of calculated and experimentallyobserved carrier migration directions, we suggest a favorable junction for the efficient separation of photogenerated carriers which has a type-II band alignment with 0.35 eV higher valance band of α−Ga2O3 than that of β-Ga2O3, and the conduction band offset of only 0.07 eV. It seems that the electron migration across the phase boundary from the α− to β−Ga2O3 mainly follows the adiabatic electron-transfer mechanism due to the strong orbital coupling between the conduction bands of two phase materials.

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“…20,21 For interface systems such as Si/SiO 2 , Ge/GeO 2 , and ZnO/GaN, the valence band offsets, which were underestimated by GGA, were shown to be improved by hybrid functional or QP calculations. 12,[40][41][42] On the other hand, for Si/HfO 2 and Si/ZrO 2 , both GGA and QP calculations well describe the valence band offsets due to the cancellation of many-body corrections in Si and oxide bulk systems. 10,43 In metal/oxide interfaces, hybrid or QP corrections will be larger for bulk HfO 2 and thus significantly modify the Schottky barrier height.…”

Section: Band Edge Corrections and Effective Work Functionmentioning

confidence: 89%

Hybrid functional versus quasiparticle calculations for the Schottky barrier and effective work function at TiN/HfO2interface

Lee

Noh

et al. 2013

Phys. Rev. B

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We investigate the Schottky barrier and effective work function (EWF) at TiN/HfO 2 interface through density functional calculations. For different interfaces that consist of either Ti-O or N-Hf interface bonds, the intrinsic metal-induced gap states are nearly independent of the interface structure, with similar decay lengths into the oxide. Due to the weak Fermi-level pinning, the EWF is more sensitive to the extrinsic effect of interface bonding. As N-rich interface bonds are replaced by O-rich bonds, the EWF decreases by up to 0.36 eV, which is attributed to the formation of opposing interface dipoles. To improve the band gap and EWF, we perform both hybrid functional and quasiparticle (QP) calculations. In the GW 0 approximation, in which the Green's function is self-consistently calculated by updating only QP energies and the full frequency-dependent dielectric function is used, the agreement of the EWF with experiment is greatly improved, while QP calculations at the G 0 W 0 level or using the plasmon-pole dielectric function tend to overestimate the EWF. In the self-consistent GW approach, in which both QP energies and wave functions are updated in iterations, the band gap is overestimated, resulting in the lower EWF. On the other hand, the EWF is severely underestimated with the hybrid functional because of the larger shift of the valence band edge level of HfO 2 .

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Hybrid density functional study of band alignment in ZnO–GaN and ZnO–(Ga1−xZnx)(N1−xOx)–GaN heterostructures

Cited by 47 publications

References 36 publications

Band offsets between ZnGeN2, GaN, ZnO, and ZnSnN2and their potential impact for solar cells

Band offsets between ZnGeN2, GaN, ZnO, and ZnSnN2and their potential impact for solar cells

Tuning the energy band-gap of crystalline gallium oxide to enhance photocatalytic water splitting: mixed-phase junctions

Hybrid functional versus quasiparticle calculations for the Schottky barrier and effective work function at TiN/HfO2interface

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