scholarly journals MOCVD deposition of zinc and bismuth chalcogenides films on the surface of silica optical fibres

2020 ◽  
Vol 59 (4) ◽  
Author(s):  
Peter Kuznetsov ◽  
Galina Yakushcheva ◽  
Evgeny Savelyev ◽  
Vasiliy Yapaskurt ◽  
Vasiliy Shcherbakov ◽  
...  
Keyword(s):  
Chemical Vapour ◽  
Organic Chemical ◽  
Optical Fibres ◽  
Transmittance Spectra ◽  
Bismuth Chalcogenides ◽  
Generation Mode ◽  
Metal Organic ◽  
Organometallic Precursors ◽  
Fibre Ring ◽  
Short Time

Metal organic chemical vapour deposition (MOCVD) technology is adapted for the deposition of thin zinc and bismuth chalcogenides films on the surface of silica optical fibres with short tapered sections. Growth runs were carried out in a special tubular quartz reactor at atmospheric pressure of hydrogen at 425°C temperature using ZnEt2, BiMe3, Et2Te and i-Pro2Se as organometallic precursors. During the deposition of chalcogenides, the transmittance spectra of the fibre were recorded in regular short time intervals. In the transmittance spectra of the fibre with a tapered section coated by ZnSe and ZnTe, lossy mode resonances (LMR) were observed at a diameter of the tapered waist below 30 μm. After the deposition of very thin Bi2Te3 and Bi2Se3 island films on the tapered waist with a diameter about 10 μm optical fibres were built into erbium fibre ring lasers. A pulsed generation mode was achieved in some of lasers due to resonator Q-factor modulation. These results can be applied for the design of LMR fibre sensors and passively Q-switch pulsed fibre lasers.

Electron microscope characterization of MOCVD-grown gap layers on Si

1986 ◽  
Vol 44 ◽  
pp. 724-725
Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson
Keyword(s):  
Atmospheric Pressure ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Lattice Match ◽  
Si Substrates ◽  
Metal Organic ◽  
Good Lattice ◽  
Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Semiconductors

2018 ◽  
Author(s):  
L. Solymar ◽  
D. Walsh ◽  
R. R. A. Syms
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Vapour Deposition ◽  
Energy Levels ◽  
Chemical Vapour ◽  
Optical Excitation ◽  
Organic Chemical ◽  
Metal Organic ◽  
Mathematical Relations ◽  
Semiconductor Properties

Both intrinsic and extrinsic semiconductors are discussed in terms of their band structure. The acceptor and donor energy levels are introduced. Scattering is discussed, from which the conductivity of semiconductors is derived. Some mathematical relations between electron and hole densities are derived. The mobilities of III–V and II–VI compounds and their dependence on impurity concentrations are discussed. Band structures of real and idealized semiconductors are contrasted. Measurements of semiconductor properties are reviewed. Various possibilities for optical excitation of electrons are discussed. The technology of crystal growth and purification are reviewed, in particular, molecular beam epitaxy and metal-organic chemical vapour deposition.

High Mobility ZnO thin film transistors using the novel deposition of high-k dielectrics

2011 ◽  
Vol 1315 ◽  
Author(s):  
D. K. Ngwashi ◽  
R. B. M. Cross ◽  
S. Paul ◽  
Andrian P. Milanov ◽  
Anjana Devi
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Performance Metrics ◽  
Chemical Vapour ◽  
High Mobility ◽  
Hafnium Dioxide ◽  
Organic Chemical ◽  
Channel Mobility ◽  
High K ◽  
Metal Organic

ABSTRACTIn order to investigate the performance of ZnO-based thin film transistors (ZnO-TFTs), we fabricate devices using amorphous hafnium dioxide (HfO2) high-k dielectrics. Sputtered ZnO was used as the active channel layer, and aluminium source/drain electrodes were deposited by thermal evaporation, and the HfO2 high-k dielectrics are deposited by metal-organic chemical vapour deposition (MOCVD). The ZnO-TFTs with high-k HfO2 gate insulators exhibit good performance metrics and effective channel mobility which is appreciably higher in comparison to SiO2-based ZnO TFTs fabricated under similar conditions. The average channel mobility, turn-on voltage, on-off current ratio and subthreshold swing of the high-k TFTs are 31.2 cm2V-1s-1, -4.7 V, ~103, and 2.4 V/dec respectively. We compared the characteristics of a typical device consisting of HfO2 to those of a device consisting of thermally grown SiO2 to examine their potential for use as high-k dielectrics in future TFT devices.

Extended X-ray Absorption Fine Structure Studies of InGaN Epilayers

2004 ◽  
Vol 831 ◽  
Author(s):  
V. Katchkanov ◽  
K.P. O'Donnell ◽  
J.F.W. Mosselmans ◽  
S. Hernandez ◽  
R.W. Martin ◽  
...  
Keyword(s):  
Fine Structure ◽  
Bond Length ◽  
Molar Fraction ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
X Ray ◽  
Absorption Fine ◽  
Vegard’S Law ◽  
Metal Organic ◽  
X Ray Absorption

ABSTRACTThe local structure around In atoms in InGaN epilayers grown by Molecular Beam Epitaxy (MBE) and by Metal-Organic Chemical Vapour Deposition (MOCVD) was studied by means of Extended X-ray Absorption Fine Structure (EXAFS). The averaged In fraction of MOCVD grown samples ranged from 10% to 40% as estimated by Electron Probe Microanalysis (EPMA). The In fraction of MBE grown samples spanned the range from 13% to 96%. The In–N bond length was found to vary slightly with composition, both for MBE and MOCVD grown samples. Moreover, for the same In content, the In-N bond lengths in MOCVD samples were longer than those in MBE grown samples. In contrast, the In-In radial separations in MOCVD and MBE samples were found to be indistinguishable for the same In molar fraction. The In-Ga bond length was observed to deviate from average cation-cation distance predicted by Vegard's law for MBE grown samples which indicates alloy compositional fluctuations.

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