Strain Induced Compositional Modulations in AlGaAs Overlayers Induced by Lateral Surface Gratings

2000 ◽  
Vol 618 ◽  
Author(s):  
U. Pietsch ◽  
U. Zeimer ◽  
L. Hofmann ◽  
J. Grenzer ◽  
S. Gramlich
Keyword(s):  
Quantum Wells ◽  
Grazing Incidence ◽  
Vapour Phase ◽  
High Index ◽  
Lateral Strain ◽  
Vapour Phase Epitaxy ◽  
Al Content ◽  
Compositional Modulation ◽  
Surface Grating ◽  
Metalorganic Vapour Phase Epitaxy

ABSTRACTStrain and compositional modulation in AlxGa1−xAs layers grown by metalorganic vapour phase epitaxy (MOVPE) over a sinusoidally shaped GaAs (001) surface grating were studied by scanning electron microscopy (SEM), X-ray grazing-incidence diffraction (GID) and photoluminescence (PL). Two growth temperatures and two compositions were chosen to realize planar overlayers. By SEM a periodic reduction in Al-content was found at the valley positions of the GaAs grating. The appearance of such vertical quantum wells (VQWs) has been explained by the growth rate anisotropy between high-index and (001) planes and a curvature-induced capillarity flow of Ga. Estimated from PL energies a larger reduction of the Al-concentration in the VQW and also at the high-index sidewall facets was found than compared to predictions from the capillarity flow theory. Using depth-resolved GID we show that the formation of VQWs is accompanied by a periodic lateral strain field. Therefore we assume, that the formation of the VQWs is influenced by strain induced diffusion due to the interaction of opposite sidewall facets.

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.

Optical Properties of Light-Hole Excitons in MOVPE Grown (Ga,In)As-GaAs Quantum Wells

1994 ◽  
Vol 340 ◽  
Author(s):  
P. Bigenwald ◽  
O. Laire ◽  
X. Zhang ◽  
O. Briot ◽  
B. Gil ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Growth Parameters ◽  
Vapour Phase ◽  
Light Hole ◽  
Type I ◽  
Vapour Phase Epitaxy ◽  
Novel Approach ◽  
Reflectivity Spectra ◽  
Metalorganic Vapour Phase Epitaxy

ABSTRACTWe study the optical properties of metalorganic vapour phase epitaxy (MOVPE) grown (Ga,In)As-GaAs single quantum wells as a function of the growth parameters. Our objective is to study the properties of the type II light-hole excitons with light-hole wave function delocalized in the thick GaAs layers and electrons confined in the ternary alloy. However, marked structures (like for type I excitons) are observed in the reflectivity spectra. This we interpret in the context of a novel approach of the exciton problem via a self-consistent calculation of the electron-hole interaction.

scholarly journals Structural Characterization of Doped Thick Gainnas Layers - Ambiguities and Challenges

2014 ◽  
Vol 65 (5) ◽  
pp. 299-303 ◽  
Author(s):  
Damian Pucicki ◽  
Katarzyna Bielak ◽  
Beata Ściana ◽  
Wojciech Dawidowski ◽  
Karolina Żelazna ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Structural Characterization ◽  
Atmospheric Pressure ◽  
Vapour Phase ◽  
Light Sources ◽  
Vapour Phase Epitaxy ◽  
Long Wavelength ◽  
Metalorganic Vapour Phase Epitaxy ◽  
Thick Layers

Abstract GaInNAs alloys are mostly used as an active part of light sources for long wavelength telecom applications. Beside this, these materials are used as thin quantum wells (QWs), and a need is to grow thick layers of such semiconductor alloys for photodetectors and photovoltaic cells applications. However, structural characterization of the GaInNAs layers is hindered by non-homogeneity of the In and N distributions along the layer. In this work the challenges of the structural characterization of doped thick GaInNAs layers grown by atmospheric pressure metalorganic vapour phase epitaxy (APMOVPE) will be presented

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.

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.

Sign in / Sign up

Export Citation Format

Share Document