Bowing of the band gap pressure coefficient in InxGa1−xN alloys

Franssen, G.; Gorczyca, I.; Suski, T.; Kamińska, A.; Pereiro, J.; Muñoz, E.; Iliopoulos, E.; Georgakilas, A.; B., S.; Ishitani, Yoshihiro; Yoshikawa, Akihiko; Christensen, N. E.; Svane, A.

doi:10.1063/1.2837072

Cited by 61 publications

(48 citation statements)

References 31 publications

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“…The PL peak emission energy obtained for all the samples investigated (not shown) was found to be in good agreement with that measured on InGaN samples of similar compositions. 30 All samples displayed a single, well-defined PL emission band, thus confirming that no measurable phase segregation is present in our samples. This was further corroborated with CL measurements, which allow one to probe the compositional homogeneity of InGaN epilayers and heterostructures at the submicron scale.…”

Section: Sample In Content (X)supporting

confidence: 56%

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy

Oliva

Ibáñez

Cuscó

et al. 2012

Journal of Applied Physics

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We use Raman scattering to investigate the composition behavior of the E 2h and A 1 (LO) phonons of In x Ga 1Àx N and to evaluate the role of lateral compositional fluctuations and in-depth strain/ composition gradients on the frequency of the A 1 (LO) bands. For this purpose, we have performed visible and ultraviolet Raman measurements on a set of high-quality epilayers grown by molecular beam epitaxy with In contents over a wide composition range (0.25 < x < 0.75). While the as-measured A 1 (LO) frequency values strongly deviate from the linear dispersion predicted by the modified random-element isodisplacement (MREI) model, we show that the strain-corrected A 1 (LO) frequencies are qualitatively in good agreement with the expected linear dependence. In contrast, we find that the strain-corrected E 2h frequencies exhibit a bowing in relation to the linear behavior predicted by the MREI model. Such bowing should be taken into account to evaluate the composition or the strain state of InGaN material from the E 2h peak frequencies. We show that in-depth strain/composition gradients and selective resonance excitation effects have a strong impact on the frequency of the A 1 (LO) mode, making very difficult the use of this mode to evaluate the strain state or the composition of InGaN material. V C 2012 American Institute of Physics.

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Section: Sample In Content (X)supporting

confidence: 56%

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy

Oliva

Ibáñez

Cuscó

et al. 2012

Journal of Applied Physics

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“…The various experimental [45][46][47][48][49][50][51][52][53] as well as theoretical [54][55][56][57][58][59][60][61][62][63][64] studies have disagreed on the magnitude of the bowing parameter.…”

Section: Alloys Ofmentioning

confidence: 99%

“…For ternary nitride alloys, such as InGaN, consensus on the band gap as a function of composition has not been reached. A number of studies have measured the band gap as a function of In content, [45][46][47][48][49][50][51][52][53] resulting in a large spread in reported band gaps. Qualitatively, there is agreement that the band gap of InGaN is a nonlinear function of alloy composition.…”

Section: Alloys Ofmentioning

confidence: 99%

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

290

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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“…In turn, several works have studied the pressure dependence of the fundamental band gap of w-InN and InGaN. [6][7][8][9][10] In general, the pressure dependence of the optical-emission peak energy in InN and InGaN is weaker than that of the absorption edge. 6,10 The observed differences have been attributed to a sizable contribution of impurity states to the optical emission of the samples.…”

Section: Introductionmentioning

confidence: 99%

High-pressure optical absorption in InN: Electron density dependence in the wurtzite phase and reevaluation of the indirect band gap of rocksalt InN

et al. 2012

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We report on high-pressure optical absorption measurements on InN epilayers with a range of free-electron concentrations (5 × 10 17 -1.6 × 10 19 cm −3 ) to investigate the effect of free carriers on the pressure coefficient of the optical band gap of wurtzite InN. With increasing carrier concentration, we observe a decrease of the absolute value of the optical band gap pressure coefficient of wurtzite InN. An analysis of our data based on the k·p model allows us to obtain a pressure coefficient of 32 meV/GPa for the fundamental band gap of intrinsic wurtzite InN. Optical absorption measurements on a 5.7-μm-thick InN epilayer at pressures above the wurtzite-to-rocksalt transition have allowed us to obtain an accurate determination of the indirect band gap energy of rocksalt InN as a function of pressure. Around the phase transition (∼15 GPa), a band gap value of 0.7 eV and a pressure coefficient of ∼23 meV/GPa are obtained.

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Bowing of the band gap pressure coefficient in InxGa1−xN alloys

Cited by 61 publications

References 31 publications

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy

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

High-pressure optical absorption in InN: Electron density dependence in the wurtzite phase and reevaluation of the indirect band gap of rocksalt InN

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Bowing of the band gap pressure coefficient in InxGa1−xN alloys

Cited by 61 publications

References 31 publications

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 &lt; x &lt; 0.75) grown by molecular beam epitaxy

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 &lt; x &lt; 0.75) grown by molecular beam epitaxy

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

High-pressure optical absorption in InN: Electron density dependence in the wurtzite phase and reevaluation of the indirect band gap of rocksalt InN

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Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy

Raman scattering by the E2h and A1(LO) phonons of InxGa1−xN epilayers (0.25 < x < 0.75) grown by molecular beam epitaxy