Arsenic mediated reconstructions on cubic (001) GaN

Feuillet, G.; Hamaguchi, Hiroshi; Ohta, Katsumi; Hacke, Peter; Okumura, Hajime; Yoshida, Sadafumi

doi:10.1063/1.118433

Cited by 68 publications

(48 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%

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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%

“…clean GaN surface) to the (2x2) reconstruction (i.e. As covered surface) when exposing the surface with an additional As background pressure [16].…”

Section: Adsorbate Covered Polar Gan Surfacesmentioning

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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“…Based on these results it appears that the GaN (001) ͑2 3 2͒ and c͑2 3 2͒ structures obtained in growth on GaAs substrates are stabilized by As adsorption or segregation, but that the ͑1 3 4͒ is an intrinsic reconstruction of the clean surface [8].…”

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confidence: 99%

Clean and As-Covered Zinc-Blende GaN (001) Surfaces: Novel Surface Structures and Surfactant Behavior

et al. 1998

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We have investigated clean and As-covered zinc-blende GaN (001) surfaces, employing firstprinciples total-energy calculations. For clean GaN surfaces our results reveal a novel surface structure very different from the well-established dimer structures commonly observed on polar III-V (001) surfaces: The energetically most stable surface is achieved by a Peierls distortion of the truncated ͑1 3 1͒ surface rather than through addition or removal of atoms. This surface exhibits a ͑1 3 4͒ reconstruction consisting of linear Ga tetramers. Furthermore, we find that a submonolayer of arsenic significantly lowers the surface energy indicating that As may be a good surfactant. Analyzing surface energies and band structures we identify the mechanisms which govern these unusual structures and discuss how they might affect growth properties. [S0031-9007(98) Its wide direct band gap and strong chemical bonds render GaN an ideal material for optoelectronic devices in the blue͞UV region of the optical spectrum. Recently, the fabrication of highly efficient blue light emitting diodes [1] and prototypes of a blue laser have been reported [2]. However, despite progress in device fabrication an understanding of the fundamental growth mechanisms is still in its infancy, and even the atomic structure of the surface is not well understood. Only recently atomically resolved scanning tunneling micrographs have been obtained for wurtzite GaN surfaces [3]. A detailed knowledge of the properties and structure of these surfaces is crucial to improve growth in a systematic way.The stable crystal phase of GaN is the wurtzite structure. However, cubic (zinc-blende) GaN can be grown epitaxially on cubic SiC or GaAs. Cubic GaN exhibits a number of properties very appealing for device applications: It has a lower band gap than the wurtzite phase (by 0.2 eV) and can be easily cleaved. Cubic GaN has been grown, e.g., on cubic GaAs (001) substrates [4][5][6]. Growing on this substrate Brandt et al. observed in going from N-rich conditions to Ga-rich conditions a reversible sequence of reconstructions exhibiting ͑1 3 1͒, ͑2 3 2͒, and c͑2 3 2͒ reflection high energy electron diffraction (RHEED) patterns [4]. The c͑2 3 2͒ and ͑2 3 2͒ reconstructions have also been reported by other groups [6]. Scanning tunneling microscopy (STM) measurements further revealed that the ͑2 3 2͒ structure contains one dimer per surface cell, but the chemical nature of the dimer could not be resolved [7]. However, recently Feuillet et al.[8] observed a ͑1 3 4͒ (N-rich) and a ͑1 3 1͒ (Garich) reconstruction for GaN (001) grown on cubic SiC. Only when exposing these surfaces to an As background pressure the two surface reconstructions commonly found for GaN on GaAs [͑2 3 2͒ and c͑2 3 2͒] were observed.Based on these results it appears that the GaN (001) ͑2 3 2͒ and c͑2 3 2͒ structures obtained in growth on GaAs substrates are stabilized by As adsorption or segregation, but that the ͑1 3 4͒ is an intrinsic reconstruction of the clean surface [8].In this Letter we address the...

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“…27 The fitting (inset The phase transformation observed at an optimum fluence of 5x10 15 ions cm -2 may be due to sufficient accumulation of Ga from the implanted source in reducing the surface energy and simultaneously stabilizing the cubic phase which is well documented in the literature. 13,14 However, we can further explore the role of defects created in the irradiation process to understand the phase transition in details. In our earlier study, 22 we have reported enhanced dynamic annealing in as- fluctuations that can lead to nucleation sites for the second phase are those that are short ranged.…”

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confidence: 99%

“…In case of epi-film the metastable c-GaN is formed by providing lattice matching substrates for epitaxial growth and by kinetic (nonequilibrium processing using techniques like plasma assisted MBE 2,5 or LPCVD 6 ) or thermodynamic stabilization ('shift of equilibrium' adopting either Ga-rich [5][6][7][8][9] conditions or adding surfactant 13 like As to lower the surface energy 14 ) of the metastable phase. For the growth of nanostructures in the VLS process, 15 however, none of these techniques can be effectively adopted to stabilize the metastable cubic phase in a controlled fashion.…”

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Hexagonal-to-cubic phase transformation in GaN nanowires by Ga+ implantation

Dhara

Datta

et al. 2004

Applied Physics Letters

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Hexagonal to cubic phase transformation is studied in focused ion beam assisted Ga+-implanted GaN nanowires. Optical photoluminescence and cathodoluminescence studies along with highresolution transmission electron microscopic structural studies are performed to confirm the phase transformation. In one possibility, sufficient accumulation of Ga from the implanted source might have reduced the surface energy and simultaneously stabilized the cubic phase. Other potential reason may be that the fluctuations in the short-range order induced by enhanced dynamic annealing (defect annihilation) with the irradiation process stabilize the cubic phase and cause the phase transformation.

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Arsenic mediated reconstructions on cubic (001) GaN

Cited by 68 publications

References 12 publications

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

Surface Structures, Surfactants and Diffusion at Cubic and Wurtzite GaN

Clean and As-Covered Zinc-Blende GaN (001) Surfaces: Novel Surface Structures and Surfactant Behavior

Hexagonal-to-cubic phase transformation in GaN nanowires by Ga+ implantation

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