Essential Change in Crystal Qualities of GaN Films by Controlling Lattice Polarity in Molecular Beam Epitaxy

Shen, Xu–Qiang; Ide, Toshihide; Cho, Sung-Hwan; Shimizu, Mitsuaki; Hara, Shiro; Okumura, Hajime; Sonoda, Saki; Shimizu, Saburo

doi:10.1143/jjap.39.l16

Cited by 55 publications

(46 citation statements)

References 11 publications

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“…The polarity of the film assumed to be mainly N-polarity by CAICISS. 5) In Fig. 2, high density of domains crosses over the GaN film.…”

Section: Atomic Resolution Observation Of Gan Filmmentioning

confidence: 94%

“…5). The samples were sliced perpendicular to the interface, followed by mechanical polishing and dimpling down to 10 µm and ion thinning using an Ar + beam under an accelerating voltage of 3 kV.…”

Section: Methodsmentioning

confidence: 99%

“…The GaN film has a polar structure along the growth direction, then, Ga or N polar lattice is produced depending on the deposition process. 4,5) In contrast to a film obtained by metalorganic chemical vapor deposition (MOCVD), the lattice orientation of a film grown by conventional molecular beam epitaxy (MBE) is assumed to be mainly N-polarity. The N-polarity GaN grown by conventional MBE has a poor-quality and much effort has been made to improve the quality of the film.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] Consequently, it was found that quality of the GaN films with Ga-polarity was dramatically improved compared to those of the GaN films with N-polarity. 5) However, the reason for the quality improvement is not clear and nanostructure analysis is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…Recent techniques of the lattice-polarity characterizations, such as coaxial impact collision ion scattering spectra (CAICISS), [5][6][7][8][9] reflection high-energy electron diffraction (RHEED), 10,11) convergent beam electron diffraction (CBED), [12][13][14][15] and chemical etching only give an average information about the lattice-polarity in the film. In contrast to these techniques, conventional high-resolution electron microscopy (HREM) [16][17][18] was applied to investigate the nanostructure of the GaN film.…”

Section: Introductionmentioning

confidence: 99%

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Structure Analysis of GaN Thin Film with Inversion Domains by High Voltage Atomic Resolution Microscopy

et al. 2002

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The atomic structures and surface morphologies of three types of GaN films were investigated by high voltage atomic resolution microscopy (HVARM). By HVARM, each atomic column of Ga and N could clearly be resolved and the polarity of the film and inversion domains could be directly determined. The GaN film was grown on a sapphire substrate by molecular beam epitaxy (MBE) after nitridation of the sapphire surface. Inversion domains (IDs) crossed the whole film to the surface and made small pyramids on the surface. The small pyramids had Ga-polarity and the rest had N-polarity. A GaN film with In exposure during film growth had an almost Ga-polarity flat surface. In exposure process reduced the density of inversion domains that have a N-polarity. While a GaN film grown on an AlN buffer layer was unipolar, with a Ga-polarity. HVARM observation revealed that the density of the IDs determine the qualities and the polarity of the film.

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“…The polarity of the film assumed to be mainly N-polarity by CAICISS. 5) In Fig. 2, high density of domains crosses over the GaN film.…”

Section: Atomic Resolution Observation Of Gan Filmmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure Analysis of GaN Thin Film with Inversion Domains by High Voltage Atomic Resolution Microscopy

et al. 2002

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Growth and Characterization of InGaN/GaN Multiple Quantum Wells on Ga-Polarity GaN by Plasma-Assisted Molecular Beam Epitaxy

Shen

Ide

Shimizu

et al. 2001

phys. stat. sol. (b)

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InGaN/GaN multiple quantum-wells (MQWs) on Ga-polarity GaN by plasma-assisted molecularbeam epitaxy were grown and characterized. In-situ reflection high-energy-electron diffraction observations and high-resolution X-ray diffraction results indicated that a flat interface and a good periodicity of the InGaN/GaN heterostructures were achieved. Photoluminescence measurements revealed the superior optical properties of InGaN/GaN MQWs emitting from ultraviolet (388 nm) to green-yellow (528 nm) range with the In composition varying from 0.04 to 0.30. Stimulated-emission features by optical pumping were demonstrated, which implied the high-quality of the MBE-grown InGaN/GaN MQWs.Introduction GaN and its related alloys (AlGaN, InGaN) have attracted a great deal of attention due to its potential applications in optical and electronic devices [1][2][3][4]. At present, the InGaN-based heterostructures are mainly fabricated by the metalorganic chemical vapor deposition (MOCVD) technique. Although molecular-beam epitaxy (MBE) has many advantages over MOCVD, such as low temperature growth and p-type doping without post-annealing [5], there are only limited research works reported on the InGaN-based single and multiple quantum wells (MQWs) fabrication by the MBE technique [6,7]. We have pointed out that the quality of MBE-grown GaN films on c-face sapphire substrates can be greatly improved by controlling the lattice-polarity of the GaN films during the growth [8], to which Ga-polarity GaN films are preferred. It is well accepted that Ga-polarity GaN films are usually obtained by MOCVD growth, while the lattice orientation of MBE films grown on c-face sapphire substrates is known to be mainly N-polarity or a mixed one [9]. Recently, excellent electron mobility values of MBE-grown GaN films and AlGaN/GaN heterostructures applying the growth on the Ga-polarity mode have been reported [10][11][12]. We speculate that lattice-polarity control in MBE technique is a key point to approach the high-quality GaN films and try to extend this opinion to InGaN-based heterostructures.In this paper, we report the growth and characterizations of InGaN/GaN MQWs grown on a Ga-polarity GaN by rf-MBE. In-situ reflection high-energy-electron diffrac-

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V/III Ratio Dependence of Polarity of GaN Grown on GaAs (111)A-Ga and (111)B-As Surfaces by MOMBE

Takahashi

Nakayama

Souda

et al. 2001

phys. stat. sol. (b)

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In order to investigate the influence of the substrate polarity and growth conditions on the polarity, GaN was grown on GaAs (111)A-Ga and B-As surfaces with different V/III ratios by metalorganic molecular beam epitaxy (MOMBE). It was found that for GaN grown on GaAs (111)A-Ga surface polarity was dominant independent of the V/III ratio, but the polarity of GaN grown on GaAs (111)B depends on the V/III ratio; N polarity was dominant for high V/III ratios (N rich) and Ga polarity was dominant for low V/III ratios (Ga rich).

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Essential Change in Crystal Qualities of GaN Films by Controlling Lattice Polarity in Molecular Beam Epitaxy

Cited by 55 publications

References 11 publications

Structure Analysis of GaN Thin Film with Inversion Domains by High Voltage Atomic Resolution Microscopy

Structure Analysis of GaN Thin Film with Inversion Domains by High Voltage Atomic Resolution Microscopy

Growth and Characterization of InGaN/GaN Multiple Quantum Wells on Ga-Polarity GaN by Plasma-Assisted Molecular Beam Epitaxy

V/III Ratio Dependence of Polarity of GaN Grown on GaAs (111)A-Ga and (111)B-As Surfaces by MOMBE

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