STRUCTURAL CHARACTERISTICS OF 70 MeV Si5+ ION IRRADIATION INDUCED NANOCLUSTERS OF GALLIUM NITRIDE

2011 ◽  
Vol 10 (04n05) ◽  
pp. 823-826
Author(s):  
S. SURESH ◽  
V. GANESH ◽  
M. BALAJI ◽  
K. BASKAR ◽  
K. ASOKAN ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ion Irradiation ◽  
Structural Characteristics ◽  
Ion Beam ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Surface Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Organic Chemical ◽  
Metal Organic

70 MeV Si ions irradiation at the liquid nitrogen temperature (77 K) induced nanoclustering on GaN epilayers grown by Metal Organic Chemical Vapor Deposition (MOCVD) are reported. HRXRD rocking curves show that there are no localized amorphization due to irradiation. Atomic force microscopy images reveal the formation of nanoclusters on the surface of the irradiated samples. On increasing the fluence the number of modified regions on the surface increases and resulted in three dimensional growth of nanocluster due to overlapping and coalescence. X-ray photoelectron spectroscopy (XPS) studies confirm that the surface features are composed of GaN . The variation of carrier concentration and hall mobility with respect to ion fluence are also studied. The effects of ion-beam induced modifications on the structural, surface characteristics and electrical properties of GaN are studied and possible mechanisms responsible for the modifications are discussed.

Ingan Quantum Dots Fabricated On Aigan Surfaces -Growth Mechanism And Optical Propertiesh-

1997 ◽  
Vol 482 ◽  
Author(s):  
H. Hirayama ◽  
S. Tanaka ◽  
P. Ramvall ◽  
Y. Aoyagi
Keyword(s):  
Quantum Dots ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Energy Shift ◽  
Organic Chemical ◽  
Self Assembling ◽  
Atomic Force ◽  
Peak Energy ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractWe demonstrate photoluminescence from self- assembling InGaN quantum dots (QDs), which are artificially fabricated on AlGaN surfaces via metal- organic chemical vapor deposition. InGaN QDs are successfully fabricated by the growth mode transition from step- flow to three dimensional island formation by using anti-surfactant silicon on AlGaN surface. The diameter and height of the fabricated InGaN QDs are estimated to be ˜10nm and ˜5nm, respectively, by an atomic- force- microscope (AFM). Indium mole fraction of InxGal−x N QDs is controlled from x=˜0.22 to ˜0.52 by varying the growth temperature of QDs. Intense photoluminescence is observed even at room temperature from InGaN QDs embedded with the GaN capping layers. In addition, the temperature- dependent energy shift of the photoluminescence peak- energy shows a localization behavior.

Near-Infrared Spectroscopy with a Dispersive Waveguide Device

1997 ◽  
Vol 51 (6) ◽  
pp. 880-882 ◽  
Author(s):  
Brian R. Stallard ◽  
Robert K. Rowe ◽  
Arnold J. Howard ◽  
G. Ronald Hadley ◽  
Gregory A. Vawter ◽  
...  
Keyword(s):  
Near Infrared ◽  
Low Cost ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Discrete Source ◽  
Ethanol Solution ◽  
Organic Chemical ◽  
Ion Beam Etching ◽  
Spectral Dispersion ◽  
Metal Organic

Miniature, low-cost sensors are in demand for a variety of applications in industry, medicine, and environmental sciences. As a first step in developing such a sensor, we have etched a grating into a GaAs rib waveguide to serve as a wavelength-dispersive element. The device was fabricated with the techniques of metal-organic chemical vapor deposition, electron-beam lithography, optical lithography, and reactive ion-beam etching. While full integration is the eventual goal of this work, for the present, a functional spectrometer was constructed with the addition of a discrete source, sample cell, lenses, and detector. The waveguide spectrometer has a spectral resolution of 7.5 nm and a spectral dispersion of 0.11°/ nm. As presently configured, it functions in the spectral range of 1500 to 1600 nm. A demonstration of the analytical capability of the waveguide spectrometer is presented. The problem posed is the determination of diethanol amine in an ethanol solution (about 10 to 100 g/L). This procedure involves the detection of the first overtone of the NH stretch at 1545 nm in a moderately absorbing solvent background. The standard error of prediction for the determination was 5.4 g/L.

Analysis of the Physical and Chemical Factors Determining Compositional Variations in the MOCVD Growth of Indium Gallium Arsenide

1990 ◽  
Vol 204 ◽  
Author(s):  
Erik O. Einset ◽  
Klavs F. Jensen ◽  
Thomas F. Kuech
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Lattice Parameter ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Compositional Variations ◽  
Wall Depletion ◽  
Physical And Chemical

ABSTRACTWe present an analysis of compositional variations in the growth of the compound semiconductor, InxGal-xAs, by metal organic chemical vapor deposition (MOCVD). A three dimensional transport model for fluid flow, heat, and mass transfer is solved using the finite element method. The Delta Lattice Parameter (DLP) model is used to describe the thermodynamics of the solid solution, and the Hertz-Langmuir equation is used to calculate the evaporation rate of indium from the growing crystal. Wall depletion is incorporated by allowing for explicit wall deposition of In vapor throughout the reactor.Comparison of model predictions with experimental observations by MOCVD of InGaAs in a horizontal reactor suggests that transport phenomena lead to composition variations across the substrate, and that solution thermodynamics have little effect on the InAs incorporation rate at a given deposition temperature. However, thermodynamic factors appear to influence the change in indium incorporation with growth temperature.

Atomic Scale Aluminum and Strain Distribution in a Gan/AlxGa1−XN Heterostructure

1997 ◽  
Vol 482 ◽  
Author(s):  
Christian Kisielowski ◽  
Olaf Schmidt ◽  
Jinwei Yang
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Organic Chemical ◽  
Well Test ◽  
Lattice Constants ◽  
Resolution Electron ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractA GaN/AlxGalxN multi-quantum well test structure with Al concentrations 0 ≤ xAl ≤ 1 was utilized to investigate the growth of AlxGal–xN barrier layers deposited by metal organic chemical vapor deposition (MOCVD). A transition from a two dimensional (2D) to a three dimensional (3D) growth mode was observed in AlxGa1–xN barriers with XAl ≥ 0.75. It is argued that the transition occurs because of growth at temperatures that are low compared with the materials melting points Tmelt. The resulting rough AlxGa1–xN surfaces can be planarized by overgrowth with GaN. Quantitative high resolution electron microscopy (HREM) was applied to measure composition and strain profiles across the GaN/AlxGa1−xN stacks at an atomic level. The measurements reveal a substantial variation of lattice constants at the AlxGa1−xN/GaN interfaces that is attributed to an Al accumulation.

Quality-enhanced GaN epitaxial films on Si(111) substrates by in situ deposition of SiN on a three-dimensional GaN template

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84794-84800 ◽  
Author(s):  
Yunhao Lin ◽  
Meijuan Yang ◽  
Wenliang Wang ◽  
Zhiting Lin ◽  
Guoqiang Li
Keyword(s):  
Vapor Deposition ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Organic Chemical ◽  
3 Dimensional ◽  
In Situ Deposition ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

High-quality crack-free GaN epitaxial films were successfully grown on Si(111) substrates using metal–organic chemical vapor deposition by in situ depositing SiN on a 3-dimensional (3D) GaN template.

High-efficiency vertical-structure GaN-based light-emitting diodes on Si substrates

2018 ◽  
Vol 6 (7) ◽  
pp. 1642-1650 ◽  
Author(s):  
Wenliang Wang ◽  
Yunhao Lin ◽  
Yuan Li ◽  
Xiaochan Li ◽  
Liegen Huang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Organic Chemical ◽  
Light Emitting ◽  
Si Substrates ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

High-quality GaN-based light-emitting diode (LED) wafers have been grown on Si substrates by metal–organic chemical vapor deposition by designing epitaxial structures with AlN/Al0.24Ga0.76N buffer layers and a three-dimensional (3D) GaN layer.

Fabrication and Characterization of 4H-SiC MOSFET with MOCVD-Grown Al2O3 Gate Insulator

2007 ◽  
Vol 556-557 ◽  
pp. 787-790 ◽  
Author(s):  
Shiro Hino ◽  
Tomohiro Hatayama ◽  
Naruhisa Miura ◽  
Tatsuo Oomori ◽  
Eisuke Tokumitsu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Drain Current ◽  
Interface State ◽  
State Density ◽  
Gate Insulator ◽  
Organic Chemical ◽  
Mos Capacitors ◽  
Significant Difference ◽  
Metal Organic

We have fabricated and characterized MOS capacitors and lateral MOSFETs using Al2O3 as a gate insulator. Al2O3 films were deposited by metal-organic chemical vapor deposition (MOCVD) at temperatures as low as 190 oC using tri-ethyl-aluminum and H2O as precursors. We first demonstrate from the capacitance – voltage (C-V) measurements that the Al2O3/SiC interface has lower interface state density than the thermally-grown SiO2/SiC interface. No significant difference was observed between X-ray photoelectron spectroscopy (XPS) Si 2p spectrum from the Al2O3/SiC interface and that from the SiC substrate, which means the SiC substrate was not oxidized during the Al2O3 deposition. Next, we show that the fabricated lateral SiC-MOSFETs with Al2O3 gate insulator have good drain current – drain voltage (ID-VD) and drain current – gate voltage (ID-VG) characteristics with normally-off behavior. The obtained peak values of field-effect mobility (μFE) are between 68 and 88 cm2/Vs.

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