Phonon Dispersion Curves in Wurtzite-Structure GaN Determined by Inelastic X-Ray Scattering

Ruf, T.; Serrano, Joaquim Rigola; Cardona, M.; Pavone, P.; Pabst, Mathias; Krisch, M.; d’Astuto, Matteo; Suski, T.; Grzegory, I.; Leszczyński, M.

doi:10.1103/physrevlett.86.906

Cited by 189 publications

(116 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12) will be discussed and compared to the modes observed in cubic GaN. Recently, inelastic x-ray scattering has become an interesting technique for studying the phonon dispersion throughout the Brillouin zone [69]. When we compare our calculated dispersion curves with these experiments we find an, in general, excellent agreement.…”

Section: Zone-boundary Phonons In Gan and Alnsupporting

confidence: 69%

See 1 more Smart Citation

Lattice dynamics in GaN and AlN probed with first‐ and second‐order Raman spectroscopy

Haboeck

Siegle

Hoffmann

et al. 2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

We present a selection of our contributions to basic research on the lattice dynamical properties of group-III nitrides and their alloys. We used first-order Raman scattering to determine the zone-center phonons and their dependence on structural attributes such as stress, chemical composition, impurities, and doping. Results on the angular dispersion of the polar modes, strain distribution, coupled LO-phonon plasmon modes, multi-mode behavior in Al x Ga 1-x N, and the quantitative determination of the phase purity of cubic and hexagonal GaN are shown. Second-order Raman-scattering experiments on GaN and AlN provide information on the vibrational states throughout the entire Brillouin zone. Based on a comparison of experimental data and calculated phonon-dispersion curves we assigned the observed structures to particular phonon branches and points in the Brillouin zone. We also discuss the behavior of the optical modes under large hydrostatic pressure. 1 Introduction During the last decade group-III nitrides have been an object of increasing research because of their interesting physical properties such as an adjustable band gap (1.9 eV to 6.2 eV) by varying the composition of the alloys [1] and application as basic materials for optoelectronic devices working in the blue and ultraviolet spectral region [2][3][4]. In particular GaN and AlN can withstand high temperatures and have large piezoelectric constants which makes them suitable for applications in highfrequency devices, sensors and low-dimensional structures [5,6].Although basic information about group-III nitrides e.g. crystal-and band structure have been available for a decade several details still remained unclear. In the following review of our work we present results of first-and second-order Raman investigations on various GaN, AlN, and Al x Ga 1-x N samples and point out some remarkable details of the structural and optical properties of these materials.

show abstract

Section: Zone-boundary Phonons In Gan and Alnsupporting

confidence: 69%

“…When we compare our calculated dispersion curves with these experiments we find an, in general, excellent agreement. Differences arise in the splitting of B 1 and LO-derived branches which in our model is larger by a factor of about 2 compared to the one in Ref [69]. For details see Fig.…”

Section: Zone-boundary Phonons In Gan and Alnmentioning

confidence: 73%

Lattice dynamics in GaN and AlN probed with first‐ and second‐order Raman spectroscopy

Haboeck

Siegle

Hoffmann

et al. 2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

show abstract

“…34,35 Further phonon replicas, which appear 92.0 meV below D 2 0 X A in the freestanding sample and 92.1 meV below D 0 X A in the heteroepitaxial layer, correspond very well to the A 1 ͑LO͒ phonon energy measured in bulk GaN by Raman scattering. 34,35 In short, we conclude that the observed phonon replicas as well as the most intense TES structures observed in the heteroepitaxial layer and in the freestanding sample ͑D 2 0 X A line͒ are due to the silicon and oxygen donors, respectively. This is in accordance with the expectation that the dominant donor centers correspond to oxygen in the freestanding sample and silicon in the heteroepitaxial layer.…”

Section: Zero-field Characteristics Of Principal D 0 X Transitiomentioning

confidence: 80%

“…Another explanation of the observed effects is based on the fact that the localization of the donor wave function increases the volume available in k space for LO phonons involved in the interaction. Since the energy of the A 1 ͑LO͒ decreases as a function of k vector around the center of the Brillouin zone, 34 the energy of the lattice excitation involved in the magnetopolaron effect could be effectively lowered by a few tenths of a millielectron volt. Because oxygen and silicon donors occupy different sublattices, the coupling of the donor excitations to the lattice vibrations would be different, which in turn could result in the size of the observed effect.…”

Section: Discussionmentioning

confidence: 99%

Magnetopolaron effect on shallow donors in GaN

et al. 2006

View full text Add to dashboard Cite

Resonant interaction between longitudinal-optic ͑LO͒ phonons and electrons bound on shallow donors in GaN is studied using magnetoluminescence of neutral-donor bound excitons ͑D 0 X͒. The experiments were performed on high-quality freestanding GaN material and heteroepitaxial GaN layers grown on sapphire. In addition to the principal recombination channel of D 0 X, in which donors are left in their ground states, two-electron satellites ͑TES͒ involving different excited donor excitations, as well as replicas of the principal D 0 X transition due to LO phonons, were observed for the oxygen and silicon donors. In order to separate transitions involving ground and excited D 0 X states, variable-temperature experiments were performed. The application of high magnetic fields allows tuning of the donor excitations into resonance with the LO phonon energy. This results in a strong enhancement of TES intensity and the appearance of several anticrossing processes in the vicinity of a LO phonon replica of the principal D 0 X transition. The observed behavior is explained in terms of a resonant interaction between LO phonons and donor-bound electrons ͑magnetopolaron effect͒. The experimental data are described using a phenomenological model that combines the theory of a hydrogen atom in a magnetic field with a model which includes the effects of nonparabolicity, nonresonant polaron corrections, and the resonant magnetopolaron effect on electrons bound to donors. It was found that the interaction in the resonant magnetopolaron regime is stronger for the oxygen than for the silicon donor.

show abstract

“…This energy should be dissipated by the heat, generating the thermal phonons whose maximum energy in wurtzite GaN is about 30 meV. 21 Assuming the phonon energy,hω, is comparable to the thermal energy, k B T, at room temperature based on the high temperature approximation for phonon statistics, we can expect that nearly 10 2 order of thermal phonons would be generated for one KrF photon absorption. Additional influence of such atomic vibrations to the REDR mechanism would induce enough number of atomic movements needed for the QW intermixing.…”

Section: Fig 5 (A)mentioning

confidence: 99%

Influence of laser lift-off on optical and structural properties of InGaN/GaN vertical blue light emitting diodes

et al. 2012

View full text Add to dashboard Cite

The influences of the laser lift-off (LLO) process on the InGaN/GaN blue light emitting diode (LED) structures, grown on sapphire substrates by low-pressure metalorganic chemical vapor deposition, have been comprehensively investigated. The vertical LED structures on Cu carriers are fabricated using electroplating, LLO, and inductively coupled plasma etching processes sequentially. A detailed study is performed on the variation of defect concentration and optical properties, before and after the LLO process, employing high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) observations, cathodoluminescence (CL), photoluminescence (PL), and high-resolution X-ray diffraction (HRXRD) measurements. The SEM observations on the distribution of dislocations after the LLO show well that even the GaN layer near to the multiple quantum wells (MQWs) is damaged. The CL measurements reveal that the peak energy of the InGaN/GaN MQW emission exhibits a blue-shift after the LLO process in addition to a reduced intensity. These behaviors are attributed to a diffusion of indium through the defects created by the LLO and creation of non-radiative recombination centers. The observed phenomena thus suggest that the MQWs, the active region of the InGaN/GaN light emitting diodes, may be damaged by the LLO process when thickness of the GaN layer below the MQW is made to be 5 μm, a conventional thickness. The CL images on the boundary between the KrF irradiated and non-irradiated regions suggest that the propagation of the KrF laser beam and an accompanied recombination enhanced defect reaction, rather than the propagation of a thermal shock wave, are the main origin of the damage effects of the LLO process on the InGaN/GaN MQWs and the n-GaN layer as well

show abstract

Phonon Dispersion Curves in Wurtzite-Structure GaN Determined by Inelastic X-Ray Scattering

Cited by 189 publications

References 17 publications

Lattice dynamics in GaN and AlN probed with first‐ and second‐order Raman spectroscopy

Lattice dynamics in GaN and AlN probed with first‐ and second‐order Raman spectroscopy

Magnetopolaron effect on shallow donors in GaN

Influence of laser lift-off on optical and structural properties of InGaN/GaN vertical blue light emitting diodes

Contact Info

Product

Resources

About