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Journal ArticleDOI

On the lattice parameters of GaN

Vanya Darakchieva, +2 more
- 19 Jul 2007 - 
- Vol. 91, Iss: 3, pp 031911
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TLDR
The lattice parameters of undoped bulk GaN fabricated by hydride vapor phase epitaxy (HVPE) on (0001) sapphire and subsequent substrate removal, are precisely determined using high-resolution x-ray diffraction.
Abstract
The lattice parameters of low-defect density, undoped bulk GaN fabricated by hydride vapor phase epitaxy (HVPE) on (0001) sapphire and subsequent substrate removal, are precisely determined using high-resolution x-ray diffraction. The obtained values, c=5.18523A and a=3.18926A, are compared with the lattice parameters of freestanding HVPE GaN from different sources and found to be representative for state-of-the-art undoped HVPE bulk GaN material. A comparison with bulk GaN fabricated by the high-pressure technique and homoepitaxial GaN is made, and significant differences in the lattice parameters are found. The observed differences are discussed and a possible explanation is suggested.

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Citations
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Journal ArticleDOI

X-ray diffraction of III-nitrides

TL;DR: In this article, the basic principles of x-ray diffraction of thin films and areas of special current interest, such as analysis of non-polar, semipolar and cubic III-nitrides, are reviewed, along with the basic principle of X-ray diffusion of thin thin films, and some useful values needed in calculations, including elastic constants and lattice parameters.
Journal ArticleDOI

Carbon as a source for yellow luminescence in GaN: Isolated CN defect or its complexes

TL;DR: In this article, three carbon defects in GaN, isolated CN and its two complexes with donors CN-ON, and CN-SiGa, were studied as a cause of the yellow luminescence using accurate hybrid density functional calculation, which includes the semi-core Ga 3d electrons as valence electrons and uses a larger 300-atom supercell.
Journal ArticleDOI

Dielectric function and optical properties of Al-rich AlInN alloys pseudomorphically grown on GaN

TL;DR: In this article, a detailed discussion of the optical properties of Al-rich Al1−xInxN alloy films is presented, where the complex dielectric function between 1 and 10ÕeV was determined from spectroscopic ellipsometry measurements.
Journal ArticleDOI

Strain evolution in GaN nanowires: From free-surface objects to coalesced templates

TL;DR: In this paper, top-down fabricated GaN nanowires were used to experimentally determine the evolution of strain along the vertical direction of 1-dimensional objects, and the elastic relaxation behavior derived from optical and structural characterizations perfectly matched the numerical results of calculations based on a continuous media approach.
Journal ArticleDOI

Effects of strain and composition on the lattice parameters and applicability of Vegard"s rule in Al-rich Al1-xInxN films grown on sapphire

TL;DR: In this paper, the lattice parameters and strain evolution in Al1−xInxN films with 0.07⩽x ⩽0.22 grown on GaN-buffered sapphire substrates by metal organic vapor phase epitaxy have been studied by reciprocal space mapping.
References
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Journal ArticleDOI

Lattice parameters of gallium nitride

TL;DR: In this article, the authors measured the lattice parameters of gallium nitride using high-resolution x-ray diffraction and compared the differences between the samples in terms of their concentrations of free electrons and structural defects.
Journal ArticleDOI

Determination of the Al mole fraction and the band gap bowing of epitaxial AlxGa1−xN films

TL;DR: In this article, the exact Al mole fraction and the biaxial strain of the alloys can be calculated by an additional determination of a, using asymmetric reflections, and the results obtained by x-ray diffraction and elastic recoil detection provide evidence for the validity of Vegard's law in the AlGaN system.
Journal ArticleDOI

The role of high-temperature island coalescence in the development of stresses in GaN films

TL;DR: In this article, the formation of dislocations and stress in GaN layers grown by metalorganic vapor phase epitaxy on sapphire is investigated with regard to the average grain diameter.
Journal ArticleDOI

Thermodynamical properties of III–V nitrides and crystal growth of GaN at high N2 pressure

TL;DR: In this article, the thermodynamic properties of AIN, GaN and InN are considered and the mechanisms of nucleation and growth of GaN crystals are discussed on the basis of the experimental results.
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