Spectroscopic Characterization of Rocksalt-Type Aluminum Nitride

Keller, K.; Brendler, Erica; Schmerler, Steve; Röder, Christian; Heide, G.; Kortus, Jens; Kroke, Edwin

doi:10.1021/acs.jpcc.5b02187

Cited by 15 publications

(17 citation statements)

References 35 publications

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“…On the other hand, the high density of defects can relax the Raman selection rules and thus the pDOS of rs-AlN or rs-ScN can also be observed. According to the pDOS of rs-AlN, a high density of states is located around 700 cm À1 , which is associated with the LO(X) phonon mode [46,47], being close to the frequency observed. From the theoretical studies of rs-ScN by Paudel et al [48], the pDOS shows a high density of states at about 657 cm À1 , which corresponds to the LO(L) phonon mode.…”

Section: Resultssupporting

confidence: 58%

“…With increase in Sc content, the E 2 (high) mode shifts from 654.9 to 647:6 cm À1 and the FWHM increases from 22.4 to 44:0 cm À1 , indicating the bond softening and increasing disorder in the wurtzite Al 1Àx Sc x N lattice due to the incorporation of Sc atoms as reported by Deng et al [23]. The broad spectral feature around 715 cm À1 , observed in the spectra of the samples with a Sc content [ 25%, could be associated with the contribution of the rock-salt structure in the alloys [46][47][48][49][50]. One-phonon bands are Raman-inactive in a crystal with the rock-salt structure because of symmetry considerations [51].…”

Section: Resultssupporting

confidence: 57%

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Co-sputtering of $$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ thin films on Pt(111): a characterization by Raman and IR spectroscopies

et al. 2020

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In this work, aluminium scandium nitride ($$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ Al 1 - x Sc x N ) thin films are deposited by reactive DC magnetron co-sputtering on Pt(111) layers. The sputtering power of the Sc target is varied in a broad range up to 900 W to effectively vary the Sc content later assessed using energy-dispersive X-ray spectroscopy (EDX). We show that commonly used X-ray diffraction techniques may yield ambiguous results, and thus, additional verification is crucial to substantiate the actual composition of the sputtered thin films. Therefore, we employ optical spectroscopy techniques, such as Raman and Fourier transformed infra-red (FTIR) spectroscopies in order to study the vibrational properties of the alloys. Our Raman spectra show that low Sc content leads to a phase separation with the formation of cubic ScN and AlScN phases during the sputtering process. Nevertheless, small amounts of the wurtzite phase are detected in the rock-salt dominated samples owing to the enhancement of the $$\hbox {A}_{{1}}$$ A 1 (LO) phonon mode by the Berreman effect in the FTIR spectra. The Sc-induced shifts of the AlN phonon modes are determined in a broad range of Sc content.

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Section: Resultssupporting

confidence: 58%

Section: Resultssupporting

confidence: 57%

Co-sputtering of $$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ thin films on Pt(111): a characterization by Raman and IR spectroscopies

et al. 2020

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“…However, in addition to EELS and XANES/EXAFS, 27 Al MAS NMR can also be used to detect metallic Al and other impurities in AlN, 26 as well as other crystal phases of AlN. 27 The present study combines several experimental methods ( 27 Al MAS NMR, EXAFS, and XANES at aluminum and nitrogen K-edges) with first principles computations of XANES spectra and reverse Monte Carlo (RMC) analysis of EXAFS spectra in order to gain a better understanding of local structure in AlN nanocrystals.…”

Section: ■ Introductionmentioning

confidence: 99%

Local Structure of Nanocrystalline Aluminum Nitride

et al. 2018

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The local structure of chemical-vapor-synthesized (CVS) crystalline AlN nanoparticles is investigated by combining magic angle spinning nuclear magnetic resonance and X-ray absorption spectroscopies. Extended X-ray absorption fine structure data are analyzed by reverse Monte Carlo method, and X-ray absorption near edge structure is interpreted by first principles FEFF calculations. The measurements show behavior characteristic of partially disordered systems. Nevertheless, combined analysis of the data, supported by Rietveld refinement of X-ray diffraction patterns, leads to the conclusion that the observed behavior is due to the small size (large surface to volume ratios) of the nanoparticles (d XRD < 6 nm) and that highly crystalline wurtzite AlN is formed during the CVS process.

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“…Rocksalt structure (RS) was experimentally only observed at high pressures showing a phase transition from wurtzite to rocksalt structure . Recently, fine powder of RS, stable over several months at ambient conditions, has been prepared giving for the first time the possibility to comprehensively characterize the material by powder X‐ray diffraction .…”

Section: Introductionmentioning

confidence: 99%

“…Recently, fine powder of RS, stable over several months at ambient conditions, has been prepared [14] giving for the first time the possibility to comprehensively characterize the material by powder X-ray diffraction [15].…”

mentioning

confidence: 99%

Quasiparticle self‐consistent GW study of AIN

Bakhtatou

Meddour

2015

Physica Status Solidi (b)

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Recently, experimental fundamental quantities of a fine powder of rocksalt AlN (RS) at ambient pressure have been measured. The optical part of this experiment analyzes the phonon features observed by Raman scattering and infrared transmission. This new experimental RS measurement may provide access in the future to new experimental data on its band structure and this might make it worthwhile to reinvestigate the band structure with the best available newest methods. In this context, electronic and optical measurements of AlN semiconductor in the wurtzite, zinc‐blende, and rocksalt phases were performed within the quasiparticle self‐consistent GW (QSGW), the local density approximation (LDA), and the hybrid quasiparticle self‐consistent GW (hQSGW) approximations based on the recently developed mixed basis all‐electron full‐potential method (PMT method) that uses the augmented plane waves (APWs) and the higher localized muffin‐tin orbitals (MTOs) simultaneously. From comparison between our results and the experimental results of zinc‐blende and wurtzite structures, we have calculated some theoretical data for rocksalt structure at ambient pressure and predicted quantities such as gaps, optical spectrum, and transition energies.

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Spectroscopic Characterization of Rocksalt-Type Aluminum Nitride

Cited by 15 publications

References 35 publications

Co-sputtering of $$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ thin films on Pt(111): a characterization by Raman and IR spectroscopies

Co-sputtering of $$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ thin films on Pt(111): a characterization by Raman and IR spectroscopies

Local Structure of Nanocrystalline Aluminum Nitride

Quasiparticle self‐consistent GW study of AIN

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