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Metalorganic Vapour Phase Epitaxy (metalorganic + vapour_phase_epitaxy)
Selected AbstractsThree-dimensionally structured silicon as a substrate for the MOVPE growth of GaN nanoLEDsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2009Sönke Fündling Abstract Three-dimensionally patterned Si(111) substrates are used to grow GaN based heterostructures by metalorganic vapour phase epitaxy, with the goal of fabricating well controlled, defect reduced GaN-based nanoLEDs. In contrast to other approaches to achieve GaN nanorods, we employed silicon substrates with deep etched nanopillars to control the GaN nanorods growth by varying the size and distance of the Si pillars. The small footprint of GaN nanorods grown on Si pillars minimise the influence of the lattice mismatched substrate and improve the material quality. For the Si pillars an inductively coupled plasma dry-etching process at cryogenic temperature has been developed. An InGaN/GaN multi quantum well (MQW) structure has been incorporated into the GaN nanorods. We found GaN nanostructures grown on top of the silicon pillars with a pyramidal shape. This shape results from a competitive growth on different facets as well as from surface diffusion of the growth species. Spatially resolved optical properties of the structures are analysed by cathodoluminescence. Strongly spatial-dependent MQW emission spectra indicate the growth rate differences on top of the rods. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] MOVPE growth and optical characterization of GaAsN films with higher nitrogen concentrationsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2006F. Nakajima Abstract We have successfully grown high-N-content GaAsN films up to 5.1% on GaAs(001) substrates using tertiarybutylarsine (TBAs) as the As precursor by metalorganic vapour phase epitaxy (MOVPE). The narrow X-ray diffraction (XRD) peaks and clear Pendellosung fringes indicate that the GaAsN/GaAs interface is fairly flat and the GaAsN layers are uniform. By the photoluminescence (PL) measurement at 10 K, the clear PL peaks related to the near-band-edge transition could be detected and the bandgap energy was red-shifted to 1.16 eV in 1.9%-N GaAsN film. But, in higher N-content films no peak could be detected. So, post growth annealing in the reactor was applied to 4.7% and 5.1%-N films, and resulted in an enhancement of the PL peak intensity, and the bandgap energy of 5.1%-N film was consequently determined to be 0.95 eV at room temperature. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development of CdSSe/CdS VCSELs for Application to Laser Cathode Ray TubesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2004K. P. O'Donnell Abstract This report summarises recent progress towards the realisation of Laser Cathode Ray Tube (LCRT) devices on the basis of II,VI semiconductors. Although such devices were demonstrated over 30 years ago, using bulk crystalline materials as the active media, practical lasers that operate at room temperature for extended periods of time are not yet readily available. We aim to overcome this roadblock by reducing the threshold power densities of working lasers. By embedding heterostructures, grown using metalorganic vapour phase epitaxy (MOVPE), within all-dielectric microcavities, the necessary threshold reductions can be made. The construction and testing of an exemplar device, based upon CdSSe/CdS (hex) multiple quantum wells, is described. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Post-annealing effect upon phosphorus-doped ZnTe homoepitaxial layers grown by MOVPEPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007Katsuhiko Saito Abstract The effect of post-annealing treatment upon the photoluminescence (PL) spectra of phosphorus-doped ZnTe homoepitaxial layers grown by metalorganic vapour phase epitaxy using tris-dimethylaminophosphorus (TDMAP) has been investigated. PL properties at 4 K of the layers are dramatically improved by the post-annealing in nitrogen flow, i.e. donor,acceptor pair emission vanishes and instead free-to-bound transition emission (FB) and broadened acceptor-related excitonic emission (Ia) appear. PL intensity at room temperature is enhanced remarkably by the treatment. While the post-annealing treatment in hydrogen flow also gives an increase in PL intensity at room temperature of the layer, PL spectrum at 4 K is almost unchanged. The intensity ratio of FB to broadened Ia for the layer after post-annealing treatment in nitrogen flow increases and the broadened Ia shifts towards longer wavelength side with increasing TDMAP transport rate. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Photoluminescence and TEM characterization of (AlyGa1,y)1,xInxP layers grown on graded buffersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2007J. Novak Abstract Composition, crystallographic quality and low temperature photoluminescence of AlGaInP quaternary layers were studied. These layers were grown on the InGaP/GaP graded buffers by metalorganic vapour phase epitaxy. Final composition of the graded buffer top layer was xIn = 0.24. Incorporation of the small amount Al into quaternary led to a substantial improvement of the surface morpohology and crystallographic quality observed in cross-sectional TEM view. Incorporation of higher amount of Al (above 1%) led to the increase of lattice mismatch, decrease of In content in the alloy and to the indirect band gap. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Structural analysis of pyramidal defects in Mg-doped GaNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006A. Pretorius Abstract Pyramidal defects in GaN:Mg grown by metalorganic vapour phase epitaxy are studied by high resolution transmission electron microscopy, energy dispersive X-ray analysis and scanning transmission electron microscopy. High resolution transmission electron microscopy images were simulated using the multislice approach in order to analyse the basal plane of the pyramidal defects. The simulated images were compared quantitatively with the experimental images. Two structural models for the basal plane inversion domain boundary containing antibixbyite-type layers are presented which show the best observed agreement with the experimentally found inversion domain boundary. Nevertheless, both models still do not match the experimental images satisfactorily, indicating that some other structure than antibixbyite is present at the boundary. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Study of the activation process of Mg dopant in GaN:Mg layersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2006B. Paszkiewicz Abstract GaN:Mg layers with different concentration of Mg dopant were grown by metalorganic vapour phase epitaxy. The incorporation of Mg was verified by secondary ion mass spectroscopy. In order to dissociate Mg-related complexes and thus electrically activate the acceptor dopant, the as-grown layers were annealed in pure N2 at ,800 °C for 30 minutes. The influence of the post-growth annealing on the layer properties was studied by photoluminescence (PL) and impedance spectroscopy. Impedance spectroscopy measurement showed that the annealed samples reveal higher charge concentrations and lower sheet resistance. Moreover, the relaxation time of hole traps decreased in annealed samples by one order of magnitude compared to as-grown samples. The changes in the electrical properties have been correlated with the changes in the PL spectra. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||