The Effect of Hydrogen Concentration on Chemical Vapour Deposition Synthesis of β-Ga2O3 Nanostructures

2020 ◽  
Vol 301 ◽  
pp. 27-34 ◽  
Author(s):  
Peverga Rex Jubu ◽  
Fong Kwong Yam ◽  
Iorkyaa Ahemen
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Energy Gap ◽  
Chemical Vapour ◽  
Average Crystallite Size ◽  
Hydrogen Gas ◽  
Growth Time ◽  
Carrier Gas ◽  
Hydrogen Flow ◽  
Scalable Synthesis

Gallium oxide (β-Ga2O3) nanostructures (NSs) have been successfully obtained through a simple scalable synthesis via thermal evaporation of gallium (III) oxide powder in hydrogen-ambient chemical vapour deposition (HACVD) without the presence of carrier gas. β-Ga2O3 was deposited on Si substrate by evaporating the source material at 1000 C in a regulated hydrogen reducing atmosphere, for 120 min growth time. Hydrogen ambient was regulated by varying the flow to observed changes in the morphological, structural and optical properties of films. The samples were characterized using high resolution X-ray diffraction (HR-XRD), field-emission scanning electron microscope (FE-SEM) and UV-vis-NIR spectrophotometer. The density and quality of NSs was observed to increase with hydrogen gas supply. The rarely reported 1) dominant XRD peak of β-Ga2O3 was obtained in the event of eliminating the carrier gas which is part of the usual recipe for CVD technique. The average crystallite size and energy gap of the synthesized material was found to decrease with increased hydrogen flow rate from 176.5 to 39.8 nm and 5.47 to 4.83 eV, respectively.

Synthesis of 3-dimensional porous graphene nanosheets using electron cyclotron resonance plasma enhanced chemical vapour deposition

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84927-84935 ◽  
Author(s):  
Rajesh Thomas ◽  
G. Mohan Rao
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Graphene Nanosheets ◽  
Chemical Vapour ◽  
Hydrogen Gas ◽  
3 Dimensional ◽  
Gas Molecules ◽  
Resonance Plasma

Microwave plasma driven chemical vapour deposition was used to synthesize graphene nanosheets from a mixture of acetylene and hydrogen gas molecules.

Mechanisms in metal-organic chemical vapour deposition

1990 ◽  
Vol 330 (1610) ◽  
pp. 183-193 ◽  
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Hydrogen Abstraction ◽  
Chemical Vapour ◽  
Morphological Characteristics ◽  
Current Status ◽  
Organic Chemical ◽  
Methyl Radicals ◽  
Carrier Gas ◽  
Metal Organic

The current status of our understanding of mechanistic details of GaAs growth by metal-organic chemical vapour deposition from various starting materials is reviewed. Despite a high level of recent activity in the study of precursor decomposition and reactivity there are still considerable gaps in our knowledge; for example, a clear differentiation between homogeneous (gas phase) and heterogenous (surfacecontrolled) processes is not yet possible. The decomposition of trimethylgallium in dihydrogen as carrier gas and the concomitant production of methane may occur by means of a radical process where hydrogen is abstracted by methyl radicals from the trimethylgallium rather than from the carrier gas. Triethylgallium on the other hand also offers the possibility of B-elimination as a facile pathway and this is reflected in the ratio ethene: ethane (3:1). In the presence of arsine there is a more facile pathway for hydrogen abstraction by alkyl radicals, giving rise in the case of triethylgallium and arsine to more ethane than ethene and in the case of trimethylgallium with arsine there is a difference in the reactivity to that found in studies of its decomposition in dihydrogen alone. Several workers have therefore deduced the participation of an intermediate adduct under growth conditions because arsine and trimethylgallium lower each others’ decomposition temperature significantly. However, it should be remembered that arsine is almost certainly a better donor of hydrogen to methyl radicals than is dihydrogen. Phenylarsine has been found to be a potentially useful alternative precursor to arsine for the preparation of epitaxial GaAs. Thin films with excellent electrical and morphological characteristics have been prepared. Phenylarsine decomposes in dihydrogen to yield benzene and arsine and in the presence of trimethylgallium and triethylgallium mechanisms similar to those found with trimethylgallium and triethylgallium with arsine are suggested. These appear not to involve the dihydrogen carrier gas.

Raman Characterisation of Carbon Nanotubes Grown by Plasma Enhanced Chemical Vapour Deposition

2011 ◽  
Vol 700 ◽  
pp. 112-115
Author(s):  
Mark Alexander Bissett ◽  
Anders Jack Barlow ◽  
Joe George Shapter ◽  
Jamie Scott Quinton
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapour Deposition ◽  
High Purity ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Growth Time ◽  
Wide Range ◽  
Supporting Layer ◽  
Current Production ◽  
Excellent Method

Simple and up-scalable production of carbon nanotubes (CNTs) still remains difficult with current production methods. Plasma enhanced chemical vapour deposition (PECVD) provides an excellent method for producing high purity and large amounts of carbon nanotubes. This work demonstrates how PECVD can be used to tailor the required properties in the resultant nanotubes produced. By altering only one of the growth variables the resultant CNTs can be altered from single-walled to multi-walled. This was achieved by altering the growth temperature from 450-650°C, altering the growth time and altering the underlying catalyst and supporting layer. High purity SWCNT and MWCNT could be produced and easily distinguished leading to a wide range of applications.

Thermal Modulated Esr For The Study Of Defects In a-SiC:H Films

1994 ◽  
Vol 336 ◽  
Author(s):  
F. Demichelis ◽  
F. Giorgis ◽  
C. F. Pirri ◽  
E. Tresso ◽  
L. Ravera ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Chemical Vapour Deposition ◽  
Electron Spin ◽  
Vapour Deposition ◽  
Energy Gap ◽  
Chemical Vapour ◽  
Thermal Modulation ◽  
Defect Distribution ◽  
Spin Resonance ◽  
Silicon Based

ABSTRACTIn this work we present Thermal Modulation Electron Spin Resonance Measurements performed on a-SiC:H films prepared by Plasma Enhanced Chemical Vapour Deposition with energy gap in the range 1.8–2.5 eV. The results have been compared with previously obtained photothermal and photoconductive ones and have been interpreted by means of a defect distribution which takes into account both silicon based and carbon based defects.

Low Energy Plasma Enhanced Chemical Vapour Deposition - Plasma Enhanced Deposition of Epitaxial Si and Sige

2001 ◽  
Vol 696 ◽  
Author(s):  
Carsten Rosenblad ◽  
Matthias Kummera ◽  
Hans-Rudolf Deller ◽  
Thomas Graf ◽  
Alex Dommann ◽  
...  
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
High Growth ◽  
Hole Mobility ◽  
High Plasma ◽  
Low Energy ◽  
Buffer Layers ◽  
Wafer Surface ◽  
Growth Time

AbstractLow energy plasma enhanced chemical vapour deposition (LEPECVD) is a deposition technique developed for the epitaxy of Si and SiGe at ultra-high deposition rates. Due to a high current plasma discharge composed of low energy particles, a high plasma enhancement can be obtained without any accompanying plasma induced damage of the wafer surface. The most important application of LEPECVD so far is for compositionally graded relaxed SiGe buffer layers. Such relaxed buffer layers are demonstrated with end composition up to pure Ge and with a growth time below 1 hour. A p-type hetero-MOSFET formed in a SiGe channel compressively strained to a Si0.5Ge0.5 relaxed buffer layer, is demonstrated as one example where the high growth rates of LEPECVD allows the synthesis of devices which cannot be produced with an acceptable throughput with conventional deposition methods. The room temperature effective hole mobility of 760 cm2/Vs obtained on such devices demonstrates a high structural and electrical quality of the LEPECVD material.

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