Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements

Callsen, Gordon; Reparaz, J. S.; Wagner, Markus R.; Kirste, Ronny; Nenstiel, Christian; Hoffmann, Axel; Phillips, M. R.

doi:10.1063/1.3554434

Cited by 64 publications

(68 citation statements)

References 16 publications

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“…Additionally, the small absolute PPCs of the E low 2 mode in ZnO, GaN, and AlN can be demanding for the considered DFT techniques as overall convergence must be achieved with sufficiently small error intervals. Concerning uniaxial pressure dependent Raman measurements a similar strong discrepancy between the experimental and theoretical PPCs values for the E low 2 mode was already observed for GaN [11]. Here, a DFT+LDA approach underestimated the PPC |b| of the E low 2 mode by up to a factor of four [45].…”

Section: −(2ã +B)mentioning

confidence: 67%

“…1 is identical to the system utilized in Ref. [11,29] for similar measurements on GaN and ZnO. A helium gas supply was connected to the pressure transmission chamber of the uniaxial pressure apparatus via a pressure reducing regu- (color online) Scheme of the apparatus used for the uniaxial pressure-dependent Raman measurements.…”

Section: Methodsmentioning

confidence: 99%

“…However, the correspondingã values scale from 0.77(3) for ZnO, over 0.55(5) for GaN [11], towards 0.34(3) cm −1 /GPa for AlN, providing a strong motivation for calculating the uniaxial pressure dependence of the related shear elastic constants. This directly measured scaling behavior does not only nicely match the order of the hydrostatic pressure dependencies of the shear elastic constants in ZnO, GaN, and AlN [48] but also their absolute values that scale from e.g.…”

Section: −(2ã +B)mentioning

confidence: 99%

“…[11] we already discussed the particular behavior of the PPC of the mostly bond-stretching A 1 (T O) mode by comparing ZnO and GaN. Now we can add AlN to this comparison, based on Kleinman's [51] internal strain parameter ζ = (α − β)/(α + β) containing Keating's [52] valence force field parameters α and β for bond stretching and bond bending, respectively.…”

Section: B General Offsets and The Raman Mode Anisotropymentioning

confidence: 99%

“…So far a full set of experimentally determined PDPs has been reported for e.g. GaN [11][12][13], clearly demonstrating the utility of uniaxial pressure-dependent Raman measurements as the most direct way for a precise PDP determination. A corresponding complete and consistent dataset for AlN is still a necessity as a large variance is evident in the PDP values reported so far [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements

et al. 2014

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We studied bulk crystals of wurtzite AlN by means of uniaxial pressure-dependent Raman measurements. As a result, we derive the phonon pressure coefficients and deformation potentials for all zone center optical phonon modes. For the A1 and E1 modes we further experimentally determined the uniaxial pressure dependence of their longitudinal optical -transverse optical (LO-TO) splittings. Our experimental approach delivers new insight into the large variance among previously reported phonon deformation potentials, which are predominantly based on heteroepitaxial growth of AlN and the ball-on-ring technique. Additionally, the measured phonon pressure coefficients are compared to their theoretical counterparts obtained by density functional theory implemented in the SIESTA package. Generally, we observe a good agreement between the calculated and measured phonon pressure coefficients but some particular Raman modes exhibit significant discrepancies similar to the case of wurtzite GaN and ZnO, clearly motivating the presented uniaxial pressure-dependent Raman measurements on bulk AlN crystals.

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Section: −(2ã +B)mentioning

confidence: 67%

Section: Methodsmentioning

confidence: 99%

Section: −(2ã +B)mentioning

confidence: 99%

Section: B General Offsets and The Raman Mode Anisotropymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements

et al. 2014

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Pressure‐Dependent Behavior of Defect‐Modulated Band Structure in Boron Arsenide

et al. 2020

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The recent observation of unusually high thermal conductivity exceeding 1000 W m−1 K−1 in single‐crystal boron arsenide (BAs) has led to interest in the potential application of this semiconductor for thermal management. Although both the electron/hole high mobilities have been calculated for BAs, there is a lack of experimental investigation of its electronic properties. Here, a photoluminescence (PL) measurement of single‐crystal BAs at different temperatures and pressures is reported. The measurements reveal an indirect bandgap and two donor–acceptor pair (DAP) recombination transitions. Based on first‐principles calculations and time‐of‐flight secondary‐ion mass spectrometry results, the two DAP transitions are confirmed to originate from Si and C impurities occupying shallow energy levels in the bandgap. High‐pressure PL spectra show that the donor level with respect to the conduction band minimum shrinks with increasing pressure, which affects the release of free carriers from defect states. These findings suggest the possibility of strain engineering of the transport properties of BAs for application in electronic devices.

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Raman and Photoluminescence Spectroscopic Detection of Surface-Bound Li+O2− Defect Sites in Li-Doped ZnO Nanocrystals Derived from Molecular Precursors

et al. 2011

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We present a detailed study of Raman spectroscopy and photoluminescence measurements on Li-doped ZnO nanocrystals with varying lithium concentrations. The samples were prepared starting from molecular precursors at low temperature. The Raman spectra revealed several sharp lines in the range of 100-200 cm(-1), which are attributed to acoustical phonons. In the high-energy range two peaks were observed at 735 cm(-1) and 1090 cm(-1). Excitation-dependent Raman spectroscopy of the 1090 cm(-1) mode revealed resonance enhancement at excitation energies around 2.2 eV. This energy coincides with an emission band in the photoluminescence spectra. The emission is attributed to the deep lithium acceptor and intrinsic point defects such as oxygen vacancies. Based on the combined Raman and PL results, we introduce a model of surface-bound LiO(2) defect sites, that is, the presence of Li(+)O(2)(-) superoxide. Accordingly, the observed Raman peaks at 735 cm(-1) and 1090 cm(-1) are assigned to Li-O and O-O vibrations of LiO(2).

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Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements

Cited by 64 publications

References 16 publications

Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements

Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements

Pressure‐Dependent Behavior of Defect‐Modulated Band Structure in Boron Arsenide

Raman and Photoluminescence Spectroscopic Detection of Surface-Bound Li+O2− Defect Sites in Li-Doped ZnO Nanocrystals Derived from Molecular Precursors

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