scholarly journals Structure of GaN grown from vapour phase on a seeded layer of gallium melt formed on a boron nitride ceramic substrate

2021 ◽  
Vol 2103 (1) ◽  
pp. 012097
Author(s):  
M G Mynbaeva
Keyword(s):  
Boron Nitride ◽  
Vapour Phase ◽  
Empirical Models ◽  
Ceramic Substrate ◽  
Liquid Gallium ◽  
Polycrystalline Structure ◽  
Vapour Phase Epitaxy ◽  
Nucleation Stage

Abstract In this study, two empirical models for the growth of millimetre–thick GaN material with either highly ordered textured or polycrystalline structure on a ceramic substrate by Hydride Vapour Phase Epitaxy (HVPE) are considered. It is suggested that the specific type of the structure of GaN is determined at the nucleation stage and depends on the character of the wetting of the surface of the substrate by the liquid gallium melt.

scholarly journals Towards practical applications of quantum emitters in boron nitride

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Koperski ◽  
K. Pakuła ◽  
K. Nogajewski ◽  
A. K. Dąbrowska ◽  
M. Tokarczyk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Boron Nitride ◽  
Vapour Phase ◽  
Emission Characteristics ◽  
Vapour Phase Epitaxy ◽  
Practical Applications ◽  
Metalorganic Vapour Phase Epitaxy ◽  
Polydimethylsiloxane Films ◽  
Background Luminescence ◽  
Quantum Emitters

AbstractWe demonstrate quantum emission capabilities from boron nitride structures which are relevant for practical applications and can be seamlessly integrated into a variety of heterostructures and devices. First, the optical properties of polycrystalline BN films grown by metalorganic vapour-phase epitaxy are inspected. We observe that these specimens display an antibunching in the second-order correlation functions, if the broadband background luminescence is properly controlled. Furthermore, the feasibility to use flexible and transparent substrates to support hBN crystals that host quantum emitters is explored. We characterise hBN powders deposited onto polydimethylsiloxane films, which display quantum emission characteristics in ambient environmental conditions.

Characterization of GaAs/AlGaAs quantum wells and quantum wires by chemical lattice imaging

1994 ◽  
Vol 52 ◽  
pp. 736-737
Author(s):  
A. Carlsson ◽  
J.-O. Malm ◽  
A. Gustafsson
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Quantum Wires ◽  
Vapour Phase ◽  
Quantitative Information ◽  
Lattice Imaging ◽  
Vapour Phase Epitaxy ◽  
Metalorganic Vapour Phase Epitaxy ◽  
High Resolution Images

In this study a quantum well/quantum wire (QW/QWR) structure grown on a grating of V-grooves has been characterized by a technique related to chemical lattice imaging. This technique makes it possible to extract quantitative information from high resolution images.The QW/QWR structure was grown on a GaAs substrate patterned with a grating of V-grooves. The growth rate was approximately three monolayers per second without growth interruption at the interfaces. On this substrate a barrier of nominally Al0.35 Ga0.65 As was deposited to a thickness of approximately 300 nm using metalorganic vapour phase epitaxy . On top of the Al0.35Ga0.65As barrier a 3.5 nm GaAs quantum well was deposited and to conclude the structure an additional approximate 300 nm Al0.35Ga0.65 As was deposited. The GaAs QW deposited in this manner turns out to be significantly thicker at the bottom of the grooves giving a QWR running along the grooves. During the growth of the barriers an approximately 30 nm wide Ga-rich region is formed at the bottom of the grooves giving a Ga-rich stripe extending from the bottom of each groove to the surface.

scholarly journals Role of dislocations in nitride laser diodes with different indium content

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agata Bojarska-Cieślińska ◽  
Łucja Marona ◽  
Julita Smalc-Koziorowska ◽  
Szymon Grzanka ◽  
Jan Weyher ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Defect Density ◽  
Laser Diodes ◽  
Diffusion Path ◽  
Vapour Phase ◽  
Indium Content ◽  
Nonradiative Recombination ◽  
Light Emitters ◽  
Vapour Phase Epitaxy

AbstractIn this work we investigate the role of threading dislocations in nitride light emitters with different indium composition. We compare the properties of laser diodes grown on the low defect density GaN substrate with their counterparts grown on sapphire substrate in the same epitaxial process. All structures were produced by metalorganic vapour phase epitaxy and emit light in the range 383–477 nm. We observe that intensity of electroluminescence is strong in the whole spectral region for devices grown on GaN, but decreases rapidly for the devices on sapphire and emitting at wavelength shorter than 420 nm. We interpret this behaviour in terms of increasing importance of dislocation related nonradiative recombination for low indium content structures. Our studies show that edge dislocations are the main source of nonradiative recombination. We observe that long wavelength emitting structures are characterized by higher average light intensity in cathodoluminescence and better thermal stability. These findings indicate that diffusion path of carriers in these samples is shorter, limiting the amount of carriers reaching nonradiative recombination centers. According to TEM images only mixed dislocations open into the V-pits, usually above the multi quantum wells thus not influencing directly the emission.

ZnSe metal organic vapour-phase epitaxy on GaAs: substrate preparation as the limiting factor in ZnSe growth

1998 ◽  
Vol 184-185 ◽  
pp. 1338 ◽  
Author(s):  
D.N. Gnoth ◽  
T.L. Ng ◽  
I.B. Poole ◽  
D.A. Evans ◽  
N. Maung ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Vapour Phase ◽  
Limiting Factor ◽  
Substrate Preparation ◽  
Vapour Phase Epitaxy ◽  
Metal Organic ◽  
Organic Vapour

EXCITON AND BIEXCITON PHENOMENA IN ZINC SULPHIDE EPILAYERS

1996 ◽  
Vol 05 (04) ◽  
pp. 621-629 ◽  
Author(s):  
J. VALENTA ◽  
D. GUENNANI ◽  
A. MANAR ◽  
P. GILLIOT
Keyword(s):  
Optical Gain ◽  
Vapour Phase ◽  
Zinc Sulphide ◽  
Detailed Characterization ◽  
Vapour Phase Epitaxy ◽  
Nanosecond Lasers ◽  
Metal Organic ◽  
Organic Vapour ◽  
Linear Optical Properties

The detailed characterization of metal organic vapour phase epitaxy grown ZnS layers on GaAs is the first step towards the study of their different non-linear optical properties performed with nanosecond lasers. Biexciton phenomena (with a binding energy of about 10 meV) are observed in photoluminescence-excitation and optical-gain spectra.

High capability, quasi-closed growth system for isothermal vapour phase epitaxy of (Hg, Cd)Te

1988 ◽  
Vol 161 ◽  
pp. 157-169 ◽  
Author(s):  
J. Piotrowski ◽  
Z. Nowak ◽  
M. Grudzien ◽  
W. Galus ◽  
K. Adamiec ◽  
...  
Keyword(s):  
Vapour Phase ◽  
Vapour Phase Epitaxy ◽  
Growth System

A Tem study of GaN Grown by ELO on (0001) 6H-SiC

1999 ◽  
Vol 595 ◽  
Author(s):  
P. Ruterana ◽  
B. Beaumont ◽  
P. Gibart ◽  
Y. Melnik
Keyword(s):  
Basal Plane ◽  
Lattice Mismatch ◽  
Early Stage ◽  
Vapour Phase ◽  
Epitaxial Layers ◽  
Prismatic Plane ◽  
Vapour Phase Epitaxy ◽  
Hexagonal Shape ◽  
To Come

AbstractThe misfit between GaN and 6H-SiC is 3.5% instead of 16% with sapphire, the epitaxial layers have similar densities of defects on both substrates. Moreover, the lattice mismatch between AlN and 6H-SiC is only 1%. Therefore, epitaxial layer overgrowth (ELO) of GaN on AlN/6H-SiC could be a route to further improve the quality of epitaxial layers. AlN has been grown by Halide Vapour Phase Epitaxy (HVPE) on (0001) 6H-SiC, thereafter a dielectric SiO2 mask was deposited and circular openings were made by standard photolithography and reactive ion etching. We have examined GaN layers at an early stage of coalescence in order to identify which dislocations bend and try to understand why. The analysed islands have always the same hexagonal shape, limited by {0110} facets. The a type dislocations are found to fold many times from basal to the prismatic plane, whereas when a+c dislocations bend to the basal plane, they were not seen to come back to a prismatic one.

Electronic structure of short-period ZnSe/ZnTe superlattices grown by MOVPE at 300ºC

1993 ◽  
Vol 308 ◽  
Author(s):  
N. Briot ◽  
T. Cloitre ◽  
O. Briot ◽  
P. Boring ◽  
B.E. Ponga ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Lattice Mismatch ◽  
Stokes Shift ◽  
Vapour Phase ◽  
Potential Candidate ◽  
High Quality ◽  
Vapour Phase Epitaxy ◽  
Light Emitting Devices ◽  
Short Period ◽  
Movpe Growth

ABSTRACTThe ZnSe-ZnTe combination is a potential candidate for the realisation of visible light-emitting devices. The lattice mismatch between bulk ZnSe and bulk ZnTe is important (∼ 8%). Therefore, their hetero-structures are strained and high quality superlattices will only be grown if having small periods. This prescription can be fulfilled in the case of metal organic vapour phase epitaxy (MOVPE) growth by combining triethylamine dimethyl zinc adduct with di-isopropyl telluride as precursors for the growth of the ZnTe layers. The growth of high quality ZnTe can then be performed at a temperature of 300ºC , close to the best MOVPE-growth temperature for ZnSe (280ºC). Lowering the growth temperature of ZnTe to this value, we could thus obtain sharp interfaces. This work reports on ZnSe-ZnTe superlattices grown on ZnSe and ZnTe buffers deposited on GaAs substrates. We demonstrate that the stokes-shift between the reflectance and photoluminescence features ( ∼ 40 meV ) measured when the thickness of ZnSe layers does not exceed 20 Å, drastically increases for layer thicknesses beyond this critical value. This, we interpret in terms of the onset of plastic relaxation which favours tellurium diffusion in the ZnSe slices. Then photoluminescence spectra broaden ( contributions of trapped-excitons dominate), and observation of free excitons in reflectance become impossible. We have studied in detail the optical properties of the superlattices and compared our findings with the predictions of a multiband envelope function calculation. We show that both zone centre excitons as well as excitons associated with the miniband dispersions (saddle-point excitons) are observed in these superlattices.

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