Infrared optical anisotropy of diluted magnetic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><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:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:mi mathvariant="normal">N</mml:mi><mml:mo>∕</mml:mo><mml:mi>c</mml:mi></mml:mrow></mml:math>-sapphire epilayers grown with a GaN buffer layer by metalorganic ch

Hu, Zhigao; Weerasekara, A.B.; Dietz, N.; Perera, A. G. U.; Straßburg, Martin; Kane, Matthew H.; Ali, Asghar; Ferguson, Ian T.

doi:10.1103/physrevb.75.205320

Cited by 20 publications

(9 citation statements)

References 37 publications

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“…The calculated value for peak B is quite close to the determined position for A 1 (TO) phonon mode at 533 cm À1 . 22 From the theoretical calculations, the wavenumber position obtained for dip C is 547 and 546 cm À1 for 200 and 450 C, respectively. The calculated wavenumber positions are not dependent on the substrate temperature, and the shift toward lower wave numbers is consistent with the compressive strain present in the GaN films grown in both self-limiting ALD and decomposition limited CVD growth regime.…”

mentioning

confidence: 99%

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

Alevli¹,

Gungor²,

Haider³

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Gallium nitride films were grown by hollow cathode plasma-assisted atomic layer deposition using triethylgallium and N2/H2 plasma. An optimized recipe for GaN film was developed, and the effect of substrate temperature was studied in both self-limiting growth window and thermal decomposition-limited growth region. With increased substrate temperature, film crystallinity improved, and the optical band edge decreased from 3.60 to 3.52 eV. The refractive index and reflectivity in Reststrahlen band increased with the substrate temperature. Compressive strain is observed for both samples, and the surface roughness is observed to increase with the substrate temperature. Despite these temperature dependent material properties, the chemical composition, E1(TO), phonon position, and crystalline phases present in the GaN film were relatively independent from growth temperature. © 2015 American Vacuum Society

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confidence: 99%

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

Alevli¹,

Gungor²,

Haider³

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…This interpretation relies on the results of the spectra modelling performed using the transfer matrix method. This mode appears in the calculated spectra only if the GaN anisotropy is taken into account, so the hexagonal crystal structure is quite important for understanding the structure of the ATR spectra [37]. With the IR-ATR spectroscopy, we have been able to observe a feature appearing in both s-and p-polarizations, which we interpret as the carbon local vibration mode, based on the presented modelling results.…”

Section: Discussionmentioning

confidence: 68%

Raman and IR-ATR spectroscopy studies of heteroepitaxial structures with a GaN:C top layer

Cerqueira¹,

Vieira²,

Alves³

et al. 2017

J. Phys. D: Appl. Phys.

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Raman spectroscopy, with both resonant and non-resonant excitation, and infra-red (IR) spectroscopy, in the attenuated total reflection (ATR) configuration, was employed to study lattice vibration modes in a set of carbon-doped GaN (GaN:C) epilayers grown by metalorganic vapour phase epitaxy (MOVPE). We analyse Raman and IR-ATR spectra from the point of view of possible effects of the carbon doping, namely: (i) local vibration mode of C atom in a N sublattice (whose frequency we theoretically estimate as 768 cm-1 using an isotope defect model), and (ii) shift in the positions of longitudinal modes owing to the phonon-plasmon coupling. We find only some indirect hints of the doping effect on the resonant Raman spectra. However, we show theoretically and confirm experimentally that the IR-ATR spectroscopy can be a much more sensitive tool for this purpose, at least for the considered structures. A weak perturbation of the dielectric function of GaN:C, caused by the substitutional carbon impurity, is shown to produce a measurable dip in the ATR reflectivity spectra at ≈ 770 cm-1 , for both p-and s-polarizations. Moreover, it influences a specific (guided-wave-type) mode observed at ≈ 737 cm-1 , originating from the GaN layer, which appears in the narrow frequency window where the real parts of the two components of the dielectric tensor of the hexagonal crystal have the opposite signs. This interpretation is supported by our modelling of the whole multilayer structure using a transfer matrix formalism.

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“…Note that calculating film inhomogeneity and nonideality is not successful because of the complicated many-parameter system in the present work. More sensitive polarized spectral measurement, such as SE and variable-angle polarized reflectance, 21,26,37 could be desirable to determine these physical properties of the ZnO:As films.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, to reasonably interpret reflectance spectra measured in the limited photon energy range, a dielectric function model can be uniquely selected to reproduce the experimental data. 25,26 In this paper, the structure, lattice vibrations and photoluminescence (PL) properties of ZnO:As films deposited on silicon (100) substrates with different C As have been studied. The dielectric function from ultraviolet (UV) to visible photon energy region of the films has been investigated using reflectance spectra.…”

Section: Introductionmentioning

confidence: 99%

Concentration Dependence of Optical Properties in Arsenic-Doped ZnO Nanocrystalline Films Grown on Silicon (100) Substrates by Pulsed Laser Deposition

et al. 2009

J. Phys. Chem. C

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Arsenic (As)-doped (1% to 3%) ZnO nanocrystalline films with the grain size of 20 nm have been grown on silicon substrates by pulsed laser deposition. X-ray diffraction analysis shows that the films are polycrystalline and exhibit the hexagonal wurtzite phase. The As dopant effects on lattice vibrations and electronic transitions of the ZnO films have been investigated by Raman scattering and photoluminescence spectra at room temperature. With increasing As concentration, A 1 (LO) phonon frequency is shifted toward lower energy side of 4 cm -1 . Ultraviolet and near-infrared optical transitions can be observed and remained as a constant. Moreover, orange and green luminescence are strongly dependent on the As concentration owing to different oxygen vacancy, zinc vacancy, oxygen interstitial, and morphology. Dielectric functions of the films have been determined in the photon energy from 2.5 to 6.0 eV by near-normal incident spectral reflectance. By fitting the experimental data with the Adachi's model, [Adachi, S. Phys. ReV. B 1987, 35, 7454] the optical constants and film thickness have been uniquely extracted. It is found that the dielectric function values of the films are less than that of undoped ZnO material, which could be attributed to the As doping and the porosity of films.

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Infrared optical anisotropy of diluted magneticGa1−xMnxN∕c-sapphire epilayers grown with a GaN buffer layer by metalorganic ch

Cited by 20 publications

References 37 publications

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

Raman and IR-ATR spectroscopy studies of heteroepitaxial structures with a GaN:C top layer

Concentration Dependence of Optical Properties in Arsenic-Doped ZnO Nanocrystalline Films Grown on Silicon (100) Substrates by Pulsed Laser Deposition

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