Characterization of Chemically Vapor Deposited GaN on Sic on a Simox Substrate

1997 ◽  
Vol 3 (S2) ◽  
pp. 487-488
Author(s):  
W.L. Zhou ◽  
P. Pirouz
Keyword(s):  
Lattice Mismatch ◽  
Defect Density ◽  
Silicon Layer ◽  
Large Defect ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Transmission Electron ◽  
Potential Applications ◽  
Gan Film

GaN has been intensively studied because of its potential applications for the fabrication of blue- or ultraviolet-light emitting devices. Sapphire (α-Al2O3) is generally used as the substrate for growth of GaN film. However, the large lattice mismatch between GaN and Al2O3is a possible cause of the large defect density in the GaN films. Consequently, alternative substrates are being studied with the aim of growing films of lesser defect densities and improved opto-electronic properties. In this paper, we report a transmission electron microscopy (TEM) study of a GaN film grown on cubic SiC which has been obtained by carbonization of the top silicon layer of a SIMOX substrate, i.e. the system GaN/SiC/Si/SiO2/Si.Cross-sectional TEM specimens were prepared by the conventional sandwich technique with the foil surface normal to the Si[l10] direction. The composite sample was ground and dimpled to a thickness of ∼ 10μm, and subsequently ion thinned to electron transparency.

Growth of a-plane ZnO Thin Films on r-plane Sapphire by Plasma-assisted MBE

2005 ◽  
Vol 891 ◽  
Author(s):  
Junqing Q. Xie ◽  
J. W. Dong ◽  
A. Osinsky ◽  
P. P. Chow ◽  
Y. W. Heo ◽  
...  
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Defect Density ◽  
Zno Thin Films ◽  
Rf Plasma ◽  
Misfit Dislocations ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Small Lattice

ABSTRACTZnO thin films have been epitaxially grown on r-plane sapphire by RF-plasma-assisted molecular beam epitaxy. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies indicate that the epitaxial relationship between ZnO and r-plane sapphire is (1120)ZnO // (1102)sapphire and [0001]ZnO // [1101]sapphire. Atomic force microscopy measurements reveal islands extended along the sapphire [1101] direction. XRD omega rocking curves for the ZnO (1120) reflection measured either parallel or perpendicular to the island direction suggest the defect density anisotropy along these directions. Due to the small lattice mismatch along the ZnO [0001] direction, few misfit dislocations were observed at the ZnO/Al2O3 interface in the high-resolution cross-sectional TEM image with the zone axis along the ZnO [1100] direction.

scholarly journals Metamorphic Integration of GaInAsSb Material on GaAs Substrates for Light Emitting Device Applications

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1743
Author(s):  
Qi Lu ◽  
Andrew Marshall ◽  
Anthony Krier
Keyword(s):  
Quantum Wells ◽  
Buffer Layer ◽  
Lattice Mismatch ◽  
Cost Effective ◽  
Threading Dislocations ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Gaas Substrates ◽  
Device Applications

The GaInAsSb material has been conventionally grown on lattice-matched GaSb substrates. In this work, we transplanted this material onto the GaAs substrates in molecular beam epitaxy (MBE). The threading dislocations (TDs) originating from the large lattice mismatch were efficiently suppressed by a novel metamorphic buffer layer design, which included the interfacial misfit (IMF) arrays at the GaSb/GaAs interface and strained GaInSb/GaSb multi-quantum wells (MQWs) acting as dislocation filtering layers (DFLs). Cross-sectional transmission electron microscopy (TEM) images revealed that a large part of the dislocations was bonded on the GaAs/GaSb interface due to the IMF arrays, and the four repetitions of the DFL regions can block most of the remaining threading dislocations. Etch pit density (EPD) measurements indicated that the dislocation density in the GaInAsSb material on top of the buffer layer was reduced to the order of 106 /cm2, which was among the lowest for this compound material grown on GaAs. The light emitting diodes (LEDs) based on the GaInAsSb P-N structures on GaAs exhibited strong electro-luminescence (EL) in the 2.0–2.5 µm range. The successful metamorphic growth of GaInAsSb on GaAs with low dislocation densities paved the way for the integration of various GaInAsSb based light emitting devices on the more cost-effective GaAs platform.

TEM analysis of light emitting porous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1398-1399
Author(s):  
M. W. Cole ◽  
J. F. Harvey ◽  
R.A. Lux ◽  
D.W. Eckart
Keyword(s):  
Porous Silicon ◽  
Integrated Circuits ◽  
Light Emission ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Light Emitting ◽  
Visible Luminescence ◽  
Transmission Electron ◽  
Potential Applications ◽  
Silicon Based

The recent observations of visible light emission from porous silicon layers (PSL) have attracted much interest due to its potential applications in silicon based optoelectronic integrated circuits, optical memories and advanced display systems. To realize these potential applications this material must be fully characterized. Specifically, the microstructure must be studied in order to understand the origin of the light emission. Unfortunately, the issue of the detailed geometry of porous silicon is not fully resolved because of the difficulty in performing transmission electron microscopy (TEM) measurements on these fragile structures. One of the first microstructural studies on visible emitting PSL, presented by Cullis and Canham, showed the material to be composed of needle-like structures having a cross sectional diameter of 3nm. It was suggested that the visible luminescence in this material is due to quantum confinement of these small structures. A major limitation of this work was the method of TEM sample preparation.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

scholarly journals A Review on Graphene-Based Light Emitting Functional Devices

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4217
Author(s):  
Muhammad Junaid ◽  
M. H. Md Khir ◽  
Gunawan Witjaksono ◽  
Zaka Ullah ◽  
Nelson Tansu ◽  
...  
Keyword(s):  
Thermal Emission ◽  
Ultra Wideband ◽  
Optical Modulators ◽  
Active Materials ◽  
Linear Dispersion ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Theoretical Investigations ◽  
Recent Developments ◽  
Potential Applications

In recent years, the field of nanophotonics has progressively developed. However, constant demand for the development of new light source still exists at the nanometric scale. Light emissions from graphene-based active materials can provide a leading platform for the development of two dimensional (2-D), flexible, thin, and robust light-emitting sources. The exceptional structure of Dirac’s electrons in graphene, massless fermions, and the linear dispersion relationship with ultra-wideband plasmon and tunable surface polarities allows numerous applications in optoelectronics and plasmonics. In this article, we present a comprehensive review of recent developments in graphene-based light-emitting devices. Light emissions from graphene-based devices have been evaluated with different aspects, such as thermal emission, electroluminescence, and plasmons assisted emission. Theoretical investigations, along with experimental demonstration in the development of graphene-based light-emitting devices, have also been reviewed and discussed. Moreover, the graphene-based light-emitting devices are also addressed from the perspective of future applications, such as optical modulators, optical interconnects, and optical sensing. Finally, this review provides a comprehensive discussion on current technological issues and challenges related to the potential applications of emerging graphene-based light-emitting devices.

TEM Investigations of Cross-Sectional Prepared Organic Light Emitting Devices

2003 ◽  
Vol 9 (S03) ◽  
pp. 266-267 ◽  
Author(s):  
Bernhard Schaffer ◽  
Christoph Mitterbauer ◽  
Alexander Pogantsch ◽  
Stephan Rentenberger ◽  
Egbert Zojer ◽  
...  
Keyword(s):  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Organic Light Emitting Devices

Non-Radiative Competition in the Excitation of Erbium Implanted Silicon Light Emitting Devices

1995 ◽  
Vol 392 ◽  
Author(s):  
T Taskin ◽  
Q Huda ◽  
A Scholes ◽  
J H Evans ◽  
A R Peaker ◽  
...  
Keyword(s):  
Threshold Current ◽  
Threshold Current Density ◽  
Extended Defects ◽  
Cross Sectional ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Radiative Processes ◽  
Luminescence Efficiency ◽  
High Concentrations

AbstractThis paper reports a study of the non-radiative processes competing with the excitation of the erbium ion in layers implanted with high concentrations of erbium and oxygen. These processes reduce the luminescence efficiency of the Si:Er system and dramatically increase the threshold current density calculated to be necessary for an ultimate goal, the Si/Ge:Er LASER. Using cross sectional TEM, photoluminescence as a function of temperature and DLTS, it is demonstrated that a two stage anneal procedure which avoids the formation of extended defects and removes specific deep states is necessary to obtain efficient Er3+ excitation at high erbium concentrations. Comparisons are made with damage resulting from germanium implantation into silicon. The role of multiple stage anneals is discussed in relation to the removal of Shockley-Hall-Read recombination centres

Quantum-Dot Molecules for Potential Applications in Terahertz Devices

2004 ◽  
Vol 829 ◽  
Author(s):  
Valeria Gabriela Stoleru ◽  
Elias Towe ◽  
Chaoying Ni ◽  
Debdas Pal
Keyword(s):  
Optical Properties ◽  
Quantum Dot ◽  
Strain Field ◽  
Strain Distribution ◽  
Major Step ◽  
Cross Sectional ◽  
Electronic And Optical Properties ◽  
Quantum Dot Molecules ◽  
Transmission Electron ◽  
Potential Applications

ABSTRACTThe experimental and theoretical results of the electronic and optical properties of quantum dot artificial molecules (AMs), formed by pairs of electronically coupled quantum dots (QDs), are presented here in order to identify the necessary conditions for the development of new types of terahertz (THz) injection lasers based on intraband carrier transitions. We have performed analytical calculations to obtain the spatial strain distribution in vertically aligned (In, Ga)As QDs grown on (001) GaAs substrates by molecular beam epitaxy. Electronic coupling of the dots, mainly governed by the thickness of the separating barrier between the dot layers, is allowed due to the strain field-assisted self-organization of the dots. The calculated strain field reproduces our cross sectional high-resolution transmission electron microscopy observations very well. We further take into account the microscopic effects of the spatial strain distribution on carrier confinement potentials, and compute the electronic structure of the AM. Our calculations of the peak luminescence energies are in good agreement with our experimental results and those of others. The growth of quantum dot molecules represents a major step in tailoring the electronic and optical properties of the nanostructures.

Structural Defects and Critical Electric Field in 3C-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 431-434 ◽  
Author(s):  
Michael A. Capano ◽  
A.R. Smith ◽  
Byeung C. Kim ◽  
E.P. Kvam ◽  
S. Tsoi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Electric Field ◽  
Lattice Mismatch ◽  
Defect Density ◽  
Chemical Vapor ◽  
Structural Defects ◽  
X Ray ◽  
Transmission Electron ◽  
Current Voltage ◽  
P Type

3C-SiC p-type epilayers were grown to thicknesses of 1.5, 3, 6 and 10 μm on 2.5° off-axis Si(001) substrates by chemical vapor deposition (CVD). Silane and propane were used as precursors. Structural analysis of epilayers was performed using transmission electron microscopy (TEM), high-resolution x-ray diffractometry (HRXRD), and Raman spectroscopy. TEM showed defect densities (stacking faults, twins and dislocations) decreasing with increasing distance from the SiC/Si interface as the lattice mismatch stress is relaxed. This observation was corroborated by a monotonic decrease in HRXRD peak width (FWHM) from 780 arcsecs (1.5 μm thick epilayer) to 350 arcsecs (10 μm thick epilayer). Significant further reduction in x-ray FWHM is possible because the minimum FWHM detected is greater than the theoretical FWHM for SiC (about 12 arcsecs). Raman spectroscopy also indicates that the residual biaxial in-plane strain decreases with increasing epilayer thickness initially, but becomes essentially constant between 6 and 10 μm. Structural defect density shows the most significant reduction in the first 2 μm of growth. Phosphorus implantation was used to generate n+/p junctions for the measurement of the critical electric field in 3C-SiC. Based on current-voltage analyses, the critical electric field in p-type 3C-SiC with a doping of 2x1017 cm-3 is 1.3x106 V/cm.

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