Epitaxial growth and optical transitions of cubic GaN films

Schikora, D.; Hankeln, M.; As, D. J.; Lischka, K.; Litz, Th.; Waag, A.; Buhrow, T.; Henneberger, F.

doi:10.1103/physrevb.54.r8381

Cited by 147 publications

(88 citation statements)

References 12 publications

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“…Identical reconstructions have also been reported by Lischka et al . [15] and Feuillet et al for GaN grown on GaAs (001) [16]. For GaN on SiC, however, Feuillet et al reported a very different pattern: a (4x1) structure (under N-rich conditions) and a (1x1) reconstruction (under Ga-rich conditions) [16].…”

Section: The Cubic (001) Surfacementioning

confidence: 99%

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

Zywietz

Neugebauer

Scheffler

et al. 1998

MRS Internet j. nitride semicond. res.

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Clean and As covered zinc-blende and wurtzite GaN surfaces have been investigated employing density-functional theory calculations. For clean GaN surfaces our calculations indicate the stability of several novel surface structures that are very different from those found on traditional III-V semiconductors. Adding impurities commonly present in significant concentrations during growth strongly modifies surface reconstructions and energies. In particular, we find that arsenic has a low solubility and significantly stabilizes the cubic GaN (001) surface making it interesting as a potential surfactant. Finally, we have studied the diffusion of Ga and N adatoms on both the equilibrium and non-equilibrium surfaces. Our calculations reveal a very different diffusivity for Ga and N adatoms: While Ga adatoms are very mobile at typical growth temperatures, the diffusion of N adatoms is slower by several orders of magnitude. These results give insight into the fundamental growth mechanisms and allow conclusions concerning optimum growth conditions.

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Section: The Cubic (001) Surfacementioning

confidence: 99%

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

Zywietz

Neugebauer

Scheffler

et al. 1998

MRS Internet j. nitride semicond. res.

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“…3,4,5,6 It is possible, however, to grow thin epitaxial films of In x Ga 1−x N with the cubic zinc-blende (ZB) structure. 7,8,9,10,11,12,13,14 The phase stability of In x Ga 1−x N alloys has been the subject of several experimental 3,4 and theoretical studies 15,16,17,18,19,20,21,22,23,24 . For example, there have been more than ten calculations of the In x Ga 1−x N pseudo-binary phase diagram.…”

Section: 34mentioning

confidence: 99%

First-principles calculation of the thermodynamics ofInxGa1−xNalloys: Effect of lattice vibrations

2006

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The thermodynamics properties of the wurtzite and zinc-blende InxGa1−xN alloys are calculated using first-principles density-functional calculations. Special quasi-random structures are used to describe the disordered alloys, for x = 1/4, 1/2, and 3/4. The effect of lattice vibrations on the phase diagram, commonly omitted from semiconductor alloy phase diagram calculations, are included through first-principles calculations of phonon spectra. Inclusion of lattice vibrations leads to a large reduction in the order-disorder critical temperature (∼ 29% and ∼ 26% for the wurtzite and zincblende structures, respectively) and changes the shape of the solubility and spinodal curve through changes in the entropies of the competing phases. Neglect of such effect produces significant errors in the phase diagrams of complex ordered semiconductor compounds. The critical temperature for phase separation is 1654 K (1771 K) for the wurtzite (zinc-blende) structures. The predicted phase diagrams are in agreement with experimental measurements on MOCVD InxGa1−xN films.

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“…The MOVPE samples, predominantly also n-conducting, were grown with GaN or AlN buffer layers in order to decrease the background carrier concentration [10,11]; they are only a few µm thick. The cubic GaN samples were exclusively grown with MBE on (001) GaAs substrates [12,13]. Their thickness runs from a few nm to 1.8 µm and their free carrier concentrations (n-type) from 10 18 to 10 20 cm -3 .…”

Section: Experimental 21 Samplesmentioning

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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Epitaxial growth and optical transitions of cubic GaN films

Cited by 147 publications

References 12 publications

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

First-principles calculation of the thermodynamics ofInxGa1−xNalloys: Effect of lattice vibrations

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

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