Lattice parameters of gallium nitride

Leszczyński, M.; Teisseyre, H.; Suski, T.; Grzegory, I.; Boćkowski, Michał; Jun, J.; Porowski, S.; Pakuła, K.; Baranowski, J. M.; Foxon, C.T.; Cheng, T.S.

doi:10.1063/1.118123

Cited by 396 publications

(206 citation statements)

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“…For the purpose of introducing stress, the equilibrium lattice constant a 0 for the wurtzite GaN have been determined to be 0.319 nm and c 0 /a 0 = 1.627, which agree well with the reported results [17,18].…”

Section: Theory and Calculation Methodssupporting

confidence: 79%

Tuning linear and nonlinear optical properties of wurtzite GaN byc-axial stress

Cai¹,

Guo²

2009

J. Phys. D: Appl. Phys.

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We study the linear and nonlinear optical properties of wurtzite GaN under c-axial stress field, using density functional theory calculations. The fully structural optimization at each c-axial strain was performed. The calculated dielectric functions show that tensile c-axial strain effectively improves the linear optical efficiency, especially for the band-edge transitions, and significantly increase the mobility of electrons in the conduction band. Second-order nonlinear optical susceptibilities show that the tensile c-axial strain will enhance the zero-and low-frequency nonlinear responses of GaN. The enhancement of the nonlinear optical property is explained by the reduction of the polarization of wurtzite GaN under tensile c-axial strains. Based on these findings, we propose a method for improving the electrical and optical properties of the crystal through imposing appropriate stress on the high symmetry crystalline directions.

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Section: Theory and Calculation Methodssupporting

confidence: 79%

Tuning linear and nonlinear optical properties of wurtzite GaN byc-axial stress

Cai¹,

Guo²

2009

J. Phys. D: Appl. Phys.

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“…These cracks originate from stresses built up during cooling as a result of the difference in thermal expansion coefficient between the (001) diamond substrate and the GaN with b ¼ 1Â10 À6 K À1 and b ¼ 6:2Â10 À6 K À1 ; respectively. [33][34][35] The presence of the cracks in the layer also results from the increased coalescence of the GaN islands because cracks can only occur if the stress is built up over large areas. With no coalescence, the stresses are local, and the GaN islands can cope with them.…”

Section: Growth Temperaturementioning

confidence: 99%

“…This spread is an indication of the misalignment of the diamond substrate, but this effect is canceled out by the / rotation in the average. From the lattice parameters of stress free bulk GaN (a ¼ 3.189 Å and c ¼ 5.186 Å ) 35 , the theoretical angle of the (10 11) plane with respect to (0001) is calculated to be 61:96 . Because the theoretical angle is larger than the experimental value, it can be deduced that the ratio c/a is lower in the grown layer, which implies an amount of tensile stress parallel to the surface.…”

Section: -mentioning

confidence: 99%

Realising epitaxial growth of GaN on (001) diamond

Dreumel

Tinnemans

Heuvel

et al. 2011

Journal of Applied Physics

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By an extensive investigation of the principal growth parameters on the deposition process, we realized the epitaxial growth of crystalline wurtzite GaN thin films on single crystal (001) diamond substrates by metal organic chemical vapor deposition. From the influence of pressure, V/III ratio, and temperature, it was deduced that the growth process is determined by the mass-transport of gallium precursor material toward the substrate. The highest temperature yielded an improved epitaxial relationship between grown layer and substrate. X ray diffraction (XRD) pole figure analysis established the presence of two domains of epitaxial layers, namely (0001) h10 10i GaN k (001) [110] diamond and (0001) h10 10i GaN k (001) ½1 10 diamond, which are 90 rotated with respect to each other. The presence of these domains is explained by the occurrence of areas of (2 Â 1) and (1 Â 2) surface reconstruction of the diamond substrate. When applying highly misoriented diamond substrates toward the [110] diamond direction, one of the growth domains is suppressed and highly epitaxial GaN on (001) diamond is realized.

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“…The crystal quality of the GaN substrates is excellent as indicated by x-ray rocking curve measurements [8]. Using CuK α 1 radiation, linewidths of 20 arcsec are obtained for the (0002) reflex.…”

Section: Substrate Preparationmentioning

confidence: 99%

GaN Homoepitaxy for Device Applications

Kamp

Kirchner

Schwegler

et al. 1999

MRS Internet j. nitride semicond. res.

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Epitaxial growth on GaN single bulk crystals sets new standards in GaN material quality. The outstanding properties provide new insights into fundamental material parameters (e.g. lattice constants, exciton binding energies, etc.) being not accessible by heteroepitaxial growth on sapphire or SiC. With MOVPE and MBE we realized unstrained GaN layers with dislocation densities about six orders of magnitude lower than in heteroepitaxy. Those layers revealed an exceptional optical quality as determined by a reduction of the photoluminescence linewidth from 5 to 0.1 meV and a reduced XRD rocking curve width from 400 to 20 arcsec.Only recently, progress in surface preparation allowed morphologies of the layers suitable for device applications. We report on InGaN/GaN MQW structures as well as the first GaN pnand InGaN/GaN double heterostructure LEDs on GaN single bulk crystals. Those LEDs are twice as bright as their counterparts grown on sapphire. In addition they reveal an improved high power characteristics, which is attributed to an enhanced crystal quality and an increased p-doping. Time resolved electroluminescence measurements proof that band/band recombination is the dominant emission mechanism for the InGaN/GaN LEDs.

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Lattice parameters of gallium nitride

Cited by 396 publications

References 0 publications

Tuning linear and nonlinear optical properties of wurtzite GaN byc-axial stress

Tuning linear and nonlinear optical properties of wurtzite GaN byc-axial stress

Realising epitaxial growth of GaN on (001) diamond

GaN Homoepitaxy for Device Applications

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