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GaN Templates (gan + templates)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

MOVPE of InN films on GaN templates grown on sapphire and silicon(111) substrates

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008
Muhammad Jamil
Abstract This paper reports the study of MOVPE of InN on GaN templates grown on sapphire and silicon(111) substrates. Thermodynamic analysis of MOVPE of InN performed using NH3 as nitrogen source and the experimental findings support the droplet-free epitaxial growth of InN under high V/III ratios of input precursors. At a growth pressure of 500 Torr, the optimum growth temperature and V/III ratio of the InN film are 575,650 °C and >3 × 105, respectively. The surface RMS roughness of InN film grown GaN/sapphire template is ,0.3 nm on 2 ,m × 2 ,m area, while the RMS roughness of the InN film grown on GaN/Si (111) templates is found as ,0.7 nm. The X-ray diffraction (XRD) measurement reveals the (0002) texture of the InN film on GaN/sapphire template with a FWHM of 281 arcsec of the InN (0002) , rocking curve. For the film grown on GaN/Si template under identical growth conditions, the XRD measurements show the presence of metallic In, in addition to the (0002) orientation of InN layer. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Quantum transport in high mobility AlGaN/GaN 2DEGs and nanostructures

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006
S. Schmult
Abstract High mobility two-dimensional electron systems in GaN/AlGaN heterostructures have been realized by plasma assisted molecular beam epitaxy on GaN templates. In the density range of 1011 cm,2 to 1012 cm,2, mobility values exceeding 160000 cm2/Vs have been achieved. Scattering mechanisms that presently limit the production of higher mobility samples are discussed. We present results of a systematic study of the weak localization and antilocalization corrections to the classical conductivity at very low magnetic fields. The unambiguous observation of a conductivity maximum at B = 0 suggests that spin,orbit scattering is not negligible in GaN heterostructures as one might expect for a wide-bandgap system. We have recently realized electron transport through GaN nanostructures. We report on the transport properties of the first quantum point contacts (QPCs) in GaN. These devices are used to study one-dimensional transport in the Nitride system. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Formation of InGaN quantum dots in regularly arranged GaN nanocolumns grown by rf-plasma-assisted molecular-beam epitaxy

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2010
Hiroto Sekiguchi
Abstract InGaN quantum dots (QDs) were successfully integrated at the apex of each pyramid-topped GaN nanocolumn. Various nanocolumn arrays with different nanocolumn diameters arranged in a triangular lattice were prepared on GaN templates by Ti-mask selective-area growth (SAG) with rf-plasma-assisted molecular-beam epitaxy (rf-MBE). The photoluminescence (PL) emission wavelength from the InGaN QDs shifted from 477 to 516 nm with increasing nanocolumn diameter from 206 to 326 nm. From the Arrhenius plot of PL integrated intensity, the PL internal quantum efficiency (IQE) was evaluated to be 48.4% for the 516-nm-wavelength sample. Threading dislocations at the bottom region of the nanocolumns were bent toward the sidewall and did not propagate to the upper active layer, which contributed to the higher PL efficiency. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Thick crack-free AlGaN films deposited by facet-controlled epitaxial lateral overgrowth

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
R. Liu
Abstract Thick crack-free AlGaN films have been grown on inclined-facet GaN templates. Light emitting diodes with , = 323 nm has been achieved on these epilayers. The GaN template was grown at a low temperature in order to obtain triangle-facet growth fronts. Subsequent growth of AlGaN on this template involving a lateral overgrowth process exhibits interesting properties. The microstructure and optical characterizations were done using transmission electron microscopy and cathodoluminescence. At the AlGaN/GaN interface, a high density of dislocations was created due to lattice mismatch strain. Another unexpected set of triangular boundaries was observed inside the AlGaN layer, which grew without any change of the growth parameters. These boundaries were found to arise from domains grown in different directions. Mono-chromatic cathodoluminescence images indicate that Al content is different between the vertically-grown and the laterally-grown domains, suggesting that lattice mismatch strain exists between them. Dislocations were created at these mismatched boundaries to relax the strain. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]