Electron affinity of AlxGa1−xN(0001) surfaces

Grabowski, S; Schneider, M.; Nienhaus, Hermann; Mönch, Winfried; Dimitrov, R.; Ambacher, O.; Stutzmann, M.

doi:10.1063/1.1367275

Cited by 192 publications

(110 citation statements)

References 21 publications

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“…[94][95][96][97][98][99] The calculated electron affinity for AlN is 1.01 eV for relaxed surfaces (0.52 eV for unrelaxed), which is again within the range of reported experimental values [0.25 ± 0.3 eV, 100 1.9 eV, 101 and 0 eV (Ref. 99)].…”

Section: Electron Affinities and Ionization Potentials Of Binary Nitrsupporting

confidence: 65%

Hybrid functional investigations of band gaps and band alignments for AlN, GaN, InN, and InGaN

Moses

Miao

Yan

et al. 2011

The Journal of Chemical Physics

284

231

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Band gaps and band alignments for AlN, GaN, InN, and InGaN alloys are investigated using density functional theory with the with the Heyd-Scuseria-Ernzerhof {HSE06 [J. Heyd, G. E. Scuseria, and M. Ernzerhof, J. Chem. Phys. 134, 8207 (2003); 124, 219906 (2006)]} XC functional. The band gap of InGaN alloys as a function of In content is calculated and a strong bowing at low In content is found, described by bowing parameters 2.29 eV at 6.25% and 1.79 eV at 12.5%, indicating the band gap cannot be described by a single composition-independent bowing parameter. Valence-band maxima (VBM) and conduction-band minima (CBM) are aligned by combining bulk calculations with surface calculations for nonpolar surfaces. The influence of surface termination [(1100) mplane or (1120) a-plane] is thoroughly investigated. We find that for the relaxed surfaces of the binary nitrides the difference in electron affinities between m-and a-plane is less than 0.1 eV. The absolute electron affinities are found to strongly depend on the choice of XC functional. However, we find that relative alignments are less sensitive to the choice of XC functional. In particular, we find that relative alignments may be calculated based on Perdew-Becke-Ernzerhof [J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 134, 3865 (1996)] surface calculations with the HSE06 lattice parameters. For InGaN we find that the VBM is a linear function of In content and that the majority of the band-gap bowing is located in the CBM. Based on the calculated electron affinities we predict that InGaN will be suited for water splitting up to 50% In content.

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Section: Electron Affinities and Ionization Potentials Of Binary Nitrsupporting

confidence: 65%

Hybrid functional investigations of band gaps and band alignments for AlN, GaN, InN, and InGaN

Moses

Miao

Yan

et al. 2011

The Journal of Chemical Physics

284

231

View full text Add to dashboard Cite

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“…23 According to the Schottky-Mott (SM) theory, the SBH at the interface between graphene and AlGaN is given by φ b = φ G − χ s , where φ G = 4.5 eV is the graphene work function, 24 and χ s is the electron affinity of Al x Ga 1−x N. Since χ s decreases as x increases, the SBH also increases with x. Grabowski et al reported the electron affinities of GaN and AlN as 3.1 eV and 0.25 eV, respectively. 25 On the other hand, some other studies reported that the electron affinities of GaN and AlN are 4.2 eV and 2.05 eV, respectively. 23,26 Therefore, the calculated SBH value is dependent on the value of Al x Ga 1−x N electron affinity used in the calculation.…”

Section: Methodsmentioning

confidence: 99%

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

et al. 2016

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The current transport mechanism of graphene formed on AlxGa1−xN/GaN heterostructures with various Al mole fractions (x = 0.15, 0.20, 0.30, and 0.40) is investigated. The current–voltage measurement from graphene to AlGaN/GaN shows an excellent rectifying property. The extracted Schottky barrier height of the graphene/AlGaN/GaN contacts increases with the Al mole fraction in AlGaN. However, the current transport mechanism deviates from the Schottky-Mott theory owing to the deterioration of AlGaN crystal quality at high Al mole fractions confirmed by reverse leakage current measurement.

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“…However, for an efficient implementation, it is convenient to assume that the screened pseudopotentials are well represented by their is set to the work function, which can be obtained from experimental data 14 or obtained from ab initio calculations. In nanostructures, as superlattices or quantum wells, v + (G = 0) determines the band alignment and its value has to be set carefully.…”

Section: Construction Of Semiempirical Pseudopotentials From Bulkmentioning

confidence: 99%

Semiempirical pseudopotential approach for nitride-based nanostructures andab initiobased passivation of free surfaces

2012

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We present a semiempirical pseudopotential method based on screened atomic pseudopotentials and derived from ab initio calculations. This approach is motivated by the demand for pseudopotentials able to address nanostructures, where ab initio methods are both too costly and insufficiently accurate at the level of the local density approximation, while mesoscopic effective-mass approaches are inapplicable due to the small size of the structures along, at least, one dimension. In this work, we improve the traditional pseudopotential method by a two-step process: First, we invert a set of self-consistently determined screened ab initio potentials in wurtzite GaN for a range of unit-cell volumes, thus determining spherically symmetric and structurally averaged atomic potentials. Second, we adjust the potentials to reproduce observed excitation energies. We find that the adjustment represents a reasonably small perturbation over the potential, so that the ensuing potential still reproduces the original wave functions, while the excitation energies are significantly improved. We furthermore deal with the passivation of the dangling bonds of free surfaces which is relevant for the study of nanowires and colloidal nanoparticles. We present a methodology to derive passivant pseudopotentials from ab initio calculations. We apply our pseudopotential approach to the exploration of the confinement effects on the electronic structure of GaN nanowires.

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Electron affinity of AlxGa1−xN(0001) surfaces

Cited by 192 publications

References 21 publications

Hybrid functional investigations of band gaps and band alignments for AlN, GaN, InN, and InGaN

Hybrid functional investigations of band gaps and band alignments for AlN, GaN, InN, and InGaN

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

Semiempirical pseudopotential approach for nitride-based nanostructures andab initiobased passivation of free surfaces

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