Local strain distribution of hexagonal GaN pyramids

Hoffmann, A.; Siegle, H.; Kaschner, A.; Eckey, L.; Thomsen, C.; Christen, J.; Bertram, F.; Schmidt, Michael; Hiramatsu, Kazumasa; Kitamura, Shota; Sawaki, Nobuhiko

doi:10.1016/s0022-0248(98)00225-5

Cited by 18 publications

(17 citation statements)

References 7 publications

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“…It is noteworthy that an intense and narrow peak of NBE and no yellow emission, i.e., well-known defect-induced yellow luminescence, were observed, indicating the high crystal quality of the 3D GaN microrods. The CL results also indicated a slight blue-shift of the NBE from common NBE emission of 3.47 eV at 5 K [44,45]. This shift of the NBE in the GaN microrod is attributed to the compressive strain exerted by the mother template.…”

Section: Structural and Optical Propertiesmentioning

confidence: 82%

Controlled morphology of regular GaN microrod arrays by selective area growth with HVPE

Lekhal

Bae

Lee

et al. 2016

Journal of Crystal Growth

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Section: Structural and Optical Propertiesmentioning

confidence: 82%

Controlled morphology of regular GaN microrod arrays by selective area growth with HVPE

Lekhal

Bae

Lee

et al. 2016

Journal of Crystal Growth

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“…3a), the BE peak position increases for beam energies below 10 keV, while above this value it is redshifted about 14 meV approximately. This variation in peak energy could be attributed to local thermal effects [20,21] and residual gradient strains [22][23][24]. Fig.…”

Section: Resultsmentioning

confidence: 98%

“…This result means structural degradation from the surface towards the interface areas. Therefore, the blue-shifts of GaN emissions can be explained in terms of band-gap augmentation due to residual stress [24,26,27], to piezoelectric field effects [28] and/or band-filling process [29]. Lee et al [23] showed in GaN nanorods strong dependence of CL on electron beam irradiation.…”

Section: Resultsmentioning

confidence: 99%

“…They explain the broadening and the blue-shift of the CL peaks to residual compressive strains. Hoffmann et al [24] have evidenced by CL images and depth profiled analysis the effect of local compressive strain on the optical properties of GaN pyramids. As mentioned in recent works [30,31], our experimental results can be caused by interplay of the residual strains and local thermal effect induced by electron beam bombardment.…”

Section: Resultsmentioning

confidence: 99%

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Luminescent properties of GaN films grown on porous silicon substrate

Matoussi

Nasr

Boufaden

et al. 2010

Journal of Luminescence

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“…A remarkable result is the gradual decrease in intensity of the E 2 peak from the pyramid together with a corresponding increasing in intensity from the peak near the interface without any shift from lower to higher energies, i.e., most of the pyramid is not stressed. The reason is most likely that the 'freestanding' GaN of the pyramid is able to expand undisturbed [35].…”

Section: Configurationmentioning

confidence: 99%

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

Haboeck

Siegle

Hoffmann

et al. 2003

phys. stat. sol. (c)

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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.

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Local strain distribution of hexagonal GaN pyramids

Cited by 18 publications

References 7 publications

Controlled morphology of regular GaN microrod arrays by selective area growth with HVPE

Controlled morphology of regular GaN microrod arrays by selective area growth with HVPE

Luminescent properties of GaN films grown on porous silicon substrate

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

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