Electronic and vibrational properties of group‐III nitrides:
            <i>Ab initio</i>
            studies

Bechstedt, F.; Furthmüller, J.; Wagner, J.‐M.

doi:10.1002/pssc.200303131

Cited by 10 publications

(6 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The small 1 ( ) E A feature could be essentially hidden under the low energy tail of the 1 ( ) E B structure due to the lifetime broadening. However, the [52]. The arrows correspond to dominating interband transitions, which are related to specific absorption structures in the dielectric functions of GaN.…”

Section: Data Evaluationmentioning

confidence: 97%

Identification of van Hove singularities in the GaN dielectric function: a comparison of the cubic and hexagonal phase

Cobet¹,

Goldhahn

Richter³

et al. 2009

Physica Status Solidi (b)

View full text Add to dashboard Cite

We present a detailed analysis of interband transition structures in the dielectric function of GaN. The dielectric function of the stable wurtzite and the metastable zinc blende phase were determined by means of synchrotron spectroscopic ellipsometry in the spectral range between 3 eV and 20 eV where the most significant structures of the dielectric function are located. In the hexagonal case, both the ordinary and extraordinary dielectric tensor component was measured on GaN films with M-plane/[1 (1) over bar 00] orientation. In a comparative discussion of the two hexagonal tensor components and the zinc blende dielectric function, all prominent absorption structures were assigned to specific interband transitions at high symmetry points in the Brillouin zone. The assignment considers the individual dipole transition probabilities depending on the crystal symmetry and the geometry of the measurement. Furthermore, a detailed theoretical band-to-band analysis of dielectric function features, published by Lambrecht et al. [1], was considered. In conclusion, we suggest a new labeling of absorption structures as used in classical III-V materials like GaAs, which reflects the origin of transition structures from specific points in the respective Brillouin zones. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

show abstract

Section: Data Evaluationmentioning

confidence: 97%

Identification of van Hove singularities in the GaN dielectric function: a comparison of the cubic and hexagonal phase

Cobet¹,

Goldhahn

Richter³

et al. 2009

Physica Status Solidi (b)

View full text Add to dashboard Cite

show abstract

“…As a whole, the frequency shift of E H 2 increased almost linearly with the growth temperature except for the data at 1200 8C where the reaction mechanism transition took place. Contrary to E H 2 and A 1 -LO, E L 2 mode redshifted with the growth temperature and this abnormality could be attributed to its opposite phonon deformation potential [42]. .…”

Section: Raman Scatteringmentioning

confidence: 77%

Structure, optical spectra and biaxial stress of (0002) AlN epilayers grown on c‐sapphire by high‐temperature chemical vapor deposition

Zhang

Liu

Liang

2014

Physica Status Solidi (a)

View full text Add to dashboard Cite

(0002) AlN epilayers were grown on c‐sapphire at temperatures of 1100, 1200, 1300, 1400, and 1500 °C, respectively, by a homebuilt high‐temperature chemical vapor deposition system. The structure, optical properties and biaxial stress of these epilayers were characterized by scanning electronic microscope, XRD, Raman scattering, and UV absorption. The results revealed that smooth layers were obtained below 1400 °C, while stripe‐shaped and hexagon‐aligned islands grew on the surface of the layer at 1500 °C due to inhomogeneous nucleation in decreased supersaturation. Moreover, the narrowing FWHM of (0002) reflection and phonon modes indicated that the crystal quality improved with increasing temperature. The optical bandgap enlarged with the increasing growth temperature, owing to decreasing dislocations and domain boundaries as well as increasing compressive stress, except that the optical bandgap shrank at 1500 °C because light scattering at the rough surface of the epilayer flattened its optical absorption edge. Furthermore, the results of XRD and Raman studies demonstrated that the biaxial stress in the epilayers turned from tensile stress to compressive stress linearly below 1.8 GPa, resulting in a biaxial stress coefficient of −1.9 cm−1 GPa−1. Therefore, the improving structure together with the increasing biaxial compressive stress of the epilayer enlarged its optical bandgap with a large coefficient of −426 meV GPa−1.

show abstract

“…By using the value of Cv(ν), the average specific heat for wurtzite phase of AlN and GaN is calculated using equation (4). The specific heat is calculated for various temperatures ranging from 0K to 400K and is shown graphically in graph 3 and graph 4 for AlN and GaN respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The band gap of group-III nitrides enable these materials useful for optoelectronic devices, LED's, detectors operating in UV and visible spectrum and laser diodes. The important features of these materials like hardness, low compressibility, short bond length, high melting point and high thermal conductivity make them useful for high frequency and high power electronic device at extreme temperature [1,2,4]. These materials with large piezoelectric constant are highly significant to be used as sensors, low dimensional structures and high frequency devices [3].…”

Section: Introductionmentioning

confidence: 99%

Vibrational Properties of Wurtzite Phase of AIN and GAN

Singh¹

2017

IJRASET

View full text Add to dashboard Cite

The group-III nitrides are the semiconductors of utmost interest due to their fascinating properties and their performance under eminent conditions of temperature. Phonons play an important role in the electron transport, electron relaxation process, dynamical, thermodynamical properties, and many more properties. We have calculated the Phonon dispersion throughout the Brillouin zone, phonon density of state, specific heat and anisotropy for wurtzite phase of AlN and GaN. de Launey angular force constant model has been used in this study as this model includes many body interactions and is also better option for structures having partially covalent character. The calculated results are in good agreement with existing experimental data at zone centre and predict phonon dispersion throughout the Brillouin zone. The calculated specific heat also found to be obeying well known relation Cv = 3R. Keywords: Lattice dynamics, phonons, Phonon Dispersion Curve, Specific heat and PDOS I. INTRODUCTIONThe nitride based semiconductors have attracted a considerable attention in last two decades due to their distinguished properties especially direct and wide band energy gap. The band gap of group-III nitrides enable these materials useful for optoelectronic devices, LED's, detectors operating in UV and visible spectrum and laser diodes. The important features of these materials like hardness, low compressibility, short bond length, high melting point and high thermal conductivity make them useful for high frequency and high power electronic device at extreme temperature [1,2,4]. These materials with large piezoelectric constant are highly significant to be used as sensors, low dimensional structures and high frequency devices [3]. The phonon study of the materials is the key for dynamical, optical transitions due to phonons, structural and thermodynamical properties. Moreover non radiative electron relaxation process and electronic transport are also influenced by excitations of phonons [5]. So the most desired properties are phonon dispersion curve and phonon density of state. The group-III nitrides have two crystallographic phases Zinc blende (cubic) and wurtzite phase. The Cubic phase has high symmetry but the wurtzite phase is considered as the most stable structure for nitride [6] and also can be used under ambient conditions. The Raman scattering and inelastic neutron scattering are mostly used to study phonons experimentally in bulk material. The most experimental studies have been investigated the phonon modes at zone centre using first order Raman scattering [7]. Most of the theoretical studies are calculating electronic band structure. The vibrational properties of these materials are studied by using number of empirical methods like rigid ion model, valence force model, ab intio calculation and keating model etc. lacks physical clarity [8,9,10]. The de Launey angular force constant model gives an excellent lattice dynamical solution by involving many particle interactions. Recently Zhang et al. [2] and Fu ...

show abstract

Electronic and vibrational properties of group‐III nitrides: Ab initio studies

Cited by 10 publications

References 78 publications

Identification of van Hove singularities in the GaN dielectric function: a comparison of the cubic and hexagonal phase

Identification of van Hove singularities in the GaN dielectric function: a comparison of the cubic and hexagonal phase

Structure, optical spectra and biaxial stress of (0002) AlN epilayers grown on c‐sapphire by high‐temperature chemical vapor deposition

Vibrational Properties of Wurtzite Phase of AIN and GAN

Contact Info

Product

Resources

About