Micro-Raman characterization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">In</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">Ga</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:mi mathvariant="normal">N</mml:mi><mml:mo>∕</mml:mo><mml:mi mathvariant="normal">Ga</mml:mi><mml:mi mathvariant="normal">N</mml:mi><mml:mo>∕</mml:mo><mml:msub><mml:mi mathvaria

Kontos, A. G.; Raptis, Y. S.; Pelekanos, N. T.; Georgakilas, A.; Bellet‐Amalric, E.; Jalabert, D.

doi:10.1103/physrevb.72.155336

Cited by 52 publications

(52 citation statements)

References 31 publications

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“…As discussed in Ref. 17, it cannot be ruled out that this band has an important contribution from the B 1 silent mode. When the laser excitation approaches the direct bandgap of In x Ga 1Àx N, the A 1 (LO) band displays a dramatic intensity increase because the A 1 (LO) phonon is resonantly excited via the Fröhlich interaction mechanisms.…”

Section: Sample In Content (X)mentioning

confidence: 96%

“…Significant frequency variations of the A 1 (LO) mode of InGaN as a function of the excitation wavelength have been reported in the literature. 13,15,[17][18][19] Different effects such as strain/compositional gradients, 13,19 selective resonant excitation, 5,7,15,17 or disorder-induced breakdown of wave-vector conservation 18 have been invoked to explain the observed shifts.…”

Section: -5mentioning

confidence: 99%

“…15,16 A broad feature is also visible in all the spectra below the A 1 (LO) band. 12,13,15,17,19 The intensity of this band, which is usually labeled as "S band" in the literature, 12,17 is maximum in relation to the E 2h mode for intermediate In compositions, i.e., in the samples with the highest degree of alloy disorder. Thus, most authors attribute this feature to Raman scattering by disorder-activated optical modes arising from alloy disorder.…”

Section: Sample In Content (X)mentioning

confidence: 99%

“…Such deviations are usually attributed to the strain of the samples. 12,20 However, many authors have shown that the A 1 (LO) frequency strongly depends on the excitation wavelength and/or on temperature, and different effects have been invoked to explain the observations: i) strain and/or compositional gradients over depth; 13,19 ii) compositional inhomogeneities giving rise to selective resonant excitation of domains with a particular In content; 5,7,15,17 iii) relaxation of the wave-vector selection rule. 18 Thus, it remains necessary to identify which mechanisms are actually playing a key role in the behavior of the A 1 (LO) mode of InGaN.…”

Section: Introductionmentioning

confidence: 99%

“…3 for a review on III-V alloys). Numerous studies have been devoted to study the vibrational properties of hexagonal InGaN thin films [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and InGaN/GaN quantum wells. [22][23][24] Although it is well accepted that both the A 1 (LO) and the E 2h phonon modes of InGaN display a one-mode behavior, 15,16 there are still open questions regarding the behavior of the optical phonons in the InGaN alloy.…”

Section: Introductionmentioning

confidence: 99%

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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

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)mentioning

confidence: 96%

Section: -5mentioning

confidence: 99%

Section: Sample In Content (X)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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Cross‐sectional and surface Raman mapping of thick GaN layers

Korbutowicz¹,

Tłaczała

Kováč

et al. 2008

Cryst. Res. Technol.

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Raman scattering spectroscopy was utilized for investigation of the structural properties of thick GaN layers. These layers with thickness ~ 40 µm have been grown by HVPE technique on the sapphire substrates. The investigations have been focused on the strain distribution in GaN layer cross-section as a function of distance from an interface sapphire/GaN and mapping of the surface and of the inner layer, near the sapphire/GaN interface. From the observed phonon shifts in the Raman spectra strain differences lower than 6.4×10corresponding to stress differences of 240 MPa were estimated across the thick GaN epitaxial layer. The measurements exhibit that strain in the layer causes changes in the Raman spectra and allow determining the relaxation process in the crystal. The obtained results confirmed, that the mode frequencies in the measured Raman spectra in both directions (parallel or perpendicular to the growth direction) for layer thicknesses over 30 µm are comparable with typical values for bulk material and match the low strain in the structure due to relaxation processes.

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Surface optical phonon modes in ternary aligned crystalline InGaN/GaN multi‐quantum‐well nanopillar arrays

Dhara

Hsueh

et al. 2009

J Raman Spectroscopy

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The optical properties of focused ion beam-engraved, perfectly aligned and spatially controlled multi-quantum-well (MQW) InGaN/GaN nanopillars were investigated. Crystalline MQW nanopillars with a diameter of 30-95 nm and high aspect ratios (7 : 1-16 : 1) showed a maximum of three-fold enhancement in emission intensity per unit active area. A light-emitting contour map of Taiwan is drawn with a nanopillar structure to demonstrate the site control of the technique adopted in the present study. Raman scattering studies were used to characterize the newly created surfaces. Unknown peaks in GaN and InGaN nanostructures are identified for surface optical (SO) phonon modes with proper assignments of wave vectors using multiple excitations, and the SO mode for the ternary phase is reported for the first time.

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Micro-Raman characterization ofInxGa1−xN∕GaN∕

Cited by 52 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

Cross‐sectional and surface Raman mapping of thick GaN layers

Surface optical phonon modes in ternary aligned crystalline InGaN/GaN multi‐quantum‐well nanopillar arrays

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Micro-Raman characterization ofInxGa1−xN∕GaN∕

Cited by 52 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

Cross‐sectional and surface Raman mapping of thick GaN layers

Surface optical phonon modes in ternary aligned crystalline InGaN/GaN multi‐quantum‐well nanopillar arrays

Contact Info

Product

Resources

About

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