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plasma-enhanced-chemical-vapor-deposition
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Fabrication and Investigation of Silicon Based Nanostructures Surface Properties
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor)
Abstract
Nowadays, silicon based devices especially carbon nanotubes received lots of attentions and advancement from researchers and industries. Because of amazing electrical and mechanical properties and wide range of applications, CNTs are received a lot of attention from nanoelectronics experts. There are lots of CNT growth methods such as: Arc Discharge, Laser Ablation, Surface Decomposition, CVD and PECVD.
In this thesis, we are going to use PECVD method to synthesis CNT. A typical PECVD system includes two parallel electrodes that have been packed in vacuum chamber and gases like argon, hydrogen and NH3 are introduced to chamber as a reactant gas.
In this thesis, firs we had fixed...
In this thesis, we are going to use PECVD method to synthesis CNT. A typical PECVD system includes two parallel electrodes that have been packed in vacuum chamber and gases like argon, hydrogen and NH3 are introduced to chamber as a reactant gas.
In this thesis, firs we had fixed...
Fabrication and Characterization of Patterned Carbon Nanotubes Network on the Silicon Wafer, by Plasma Enhanced Chemical Vapor Deposition
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor)
Abstract
Carbon nanotubes, due to their extraordinary electronic and physical properties, have attracted much attention in the last decade. Some of their potential applications are in CNT-field effect transistor, field emission devices, physical and chemical sensors, micro and Nanoelectromechanical systems and Nano antenna. In this thesis, we have first reviewed some features of carbon nanotubes and the advantages of PECVD method compared with thermal CVD. In the second part the role of some of the materials (such as H2/NH3/C2H4) in CNT growth are studied. We created a square pattern on the silicon wafer by photolithography. Afterwards, titanium and nickel deposition is done on the mentioned pattern....
Co-deposition process of RF-Sputtering and RF-PECVD of copper/carbon nanocomposite films
, Article Surface and Coatings Technology ; Volume 202, Issue 12 , 2008 , Pages 2731-2736 ; 02578972 (ISSN) ; Vesaghi, M. A ; Shafiekhani, A ; Baradaran, A ; Karimi, A ; Mobini, Z ; Sharif University of Technology
2008
Abstract
Nanoparticle copper/carbon composite films were prepared by co-deposition of RF-Sputtering and RF-PECVD method from acetylene gas and copper target. We investigate deposition process in the region where by changing pressure, the process converts to physical sputtering mode in constant power regime and at a critical pressure between 1.5 to 3 Pa. The estimated value of mean ion energy at this critical point of pressure is close to threshold energy of physical sputtering of copper atoms by acetylene ions. By utilizing this property and by setting initial pressure from 1.3 to 6.6 Pa, nanoparticles copper/carbon composite films were grown with different copper content. The Copper content of our...
Plasma-enhanced chemical vapor deposition for fabrication of yolk-shell SnO2@Void@C nanowires, as an efficient carbon coating technique for improving lithium-ion battery performance
, Article Materials Science in Semiconductor Processing ; Volume 149 , 2022 ; 13698001 (ISSN) ; Mousavi, M. R ; Yasoubi, M ; Sanaee, Z ; Ghasemi, S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This manuscript describes the implementation of plasma-enhanced chemical vapor deposition (DC-PECVD) and vapor-liquid-solid (VLS) techniques to fabricate a yolk-shell SnO2@Void@C nanowire (NW) structure. SnO2 nanowires have been synthesized on the stainless steel mesh substrate through the VLS method. The PECVD-assisted growth of carbon nanolayer on the SnO2 and SiO2 coated SnO2 NWs has been performed to fabricate SnO2@C core-shell and SnO2@SiO2@C yolk-shell structures, respectively. A consequent silica etching process converted the SnO2@SiO2@C into SnO2@Void@C structure. The electrochemical performance of bare SnO2 NWs, SnO2 NWs @ C, and SnO2 @Void @ C coaxial NWs structures have been...
Thermal residual stresses in silicon thin film solar cells under operational cyclic thermal loading: A finite element analysis
, Article Solar Energy ; Volume 135 , 2016 , Pages 366-373 ; 0038092X (ISSN) ; Dehghany, M ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In manufacturing amorphous silicon solar cells, thin films are deposited at high temperatures (200-400 °C) on a thick substrate using sputtering and plasma enhanced chemical vapor deposition (PECVD) methods. Since the thin films and substrate have different thermal expansion coefficients, cooling the system from deposition temperature to room temperature induces thermal residual stresses in both the films and substrate. In addition, these stresses, especially those having been induced in the amorphous silicon layer can change the carrier mobility and band gap energy of the silicon and consequently affect the solar cell efficiency. In this paper, a 2D finite element model is proposed to...
Investigating Electrochemical Behavior of Biosensor Based on Vertically Aligned Carbon Nanotubes
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhian, Saeed (Supervisor) ; Iraji Zad, Azam (Co-Advisor) ; Mohajerzadeh, Shamsoddin (Co-Advisor) ; Vossoughi, Manoochehr (Co-Advisor)
Abstract
In this research we focus on fabrication, characterization and performance of biosensors based on vertically aligned carbon nanotubes. Carbon nanotubes have been used as high density carbon nanotubes and nanoelectrode array. Carbon nanotubes have been grown using plasma enhanced chemical vapor deposition method. Characterization and performance of biosensors have been studied by cyclic voltammetry and electrochemical impedance spectroscopy methods.
The mediator-less glutamate biosensor is prepared based on covalently attached glutamate dehydrogenase on vertically aligned carbon nanotubes. The biosensor has a low detection limit of 57 nM, two linear range of 0.1-20 µM with sensitivity of...
The mediator-less glutamate biosensor is prepared based on covalently attached glutamate dehydrogenase on vertically aligned carbon nanotubes. The biosensor has a low detection limit of 57 nM, two linear range of 0.1-20 µM with sensitivity of...
Silver nanoparticles within vertically aligned multi-wall carbon nanotubes with open tips for antibacterial purposes
, Article Journal of Materials Chemistry ; Volume 21, Issue 2 , Oct , 2011 , Pages 387-393 ; 09599428 (ISSN) ; Abdolahad, M ; Abdi, Y ; Mohajerzadeh, S ; Sharif University of Technology
2011
Abstract
Vertically aligned multi-wall carbon nanotube (CNT) arrays were fabricated in tip-growth mode on Ni/Si substrates using plasma enhanced chemical vapor deposition. In a purification process including hydrogenation and acid washing of the Ni/CNTs, the oxygen-containing functional groups were substantially reduced and a wide hollow core at the tip of the CNTs was formed by removing the Ni seeds. Sol-gel silver nanoparticles were deposited on the surface of the unpurified Ni/CNTs, while they could also be embedded within the hollow core of the Ni-removed CNTs. The persistency of the silver ions in the Ni-removed Ag-CNTs in comparison to the release of the silver ions from the Ag-Ni/CNTs in a...
Flexible free-standing vertically aligned carbon nanotube on activated reduced graphene oxide paper as a high performance lithium ion battery anode and supercapacitor
, Article Electrochimica Acta ; Volume 320 , 2019 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, S ; Mohajerzadeh, S ; Sanaee, Z ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Here, controlled growth of vertically aligned carbon nanotubes (VACNTs) on free-standing porous activated reduced graphene oxide (a-rGO) paper was fabricated using plasma-enhanced chemical vapor deposition method. The electrochemical performance of prepared film was investigated to provide effective electrode for 3D flexible high-performance lithium-ion batteries (LIBs) and supercapacitors. The results revealed that the prepared electrode exhibited a high specific capacitance of 347 F/g at 0.5 A/g in 1 M KOH electrolyte, 60% more than non-activated rGO-paper (218 F/g). The VACNTs on a-rGO have increased the accessible surface area and acted as efficient electrical conducting paths, which...
Antimony doped SnO2 nanowire@C core–shell structure as a high-performance anode material for lithium-ion battery
, Article Nanotechnology ; Volume 32, Issue 28 , 2021 ; 09574484 (ISSN) ; Abolhassani, R ; Hosseini, M ; Akbarnejad, E ; Mojallal, M. H ; Ghasemi, S ; Mohajerzadeh, S ; Sanaee, Z ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
SnO2 is considered as one of the high specific capacity anode materials for Lithium-ion batteries. However, the low electrical conductivity of SnO2 limits its applications. This manuscript reports a simple and efficient approach for the synthesis of Sb-doped SnO2 nanowires (NWs) core and carbon shell structure which effectively enhances the electrical conductivity and electrochemical performance of SnO2 nanostructures. Sb doping was performed during the vapor-liquid-solid synthesis of SnO2 NWs in a horizontal furnace. Subsequently, carbon nanolayer was coated on the NWs using the DC Plasma Enhanced Chemical Vapor Deposition approach. The carbon-coated shell improves the Solid-Electrolyte...
Synthesis of titania/carbon nanotube heterojunction arrays for photoinactivation of E. coli in visible light irradiation
, Article Carbon ; Volume 47, Issue 14 , 2009 , Pages 3280-3287 ; 00086223 (ISSN) ; Abdolahad, M ; Abdi, Y ; Mohajerzadeh, S ; Sharif University of Technology
2009
Abstract
TiO2/multi-wall carbon nanotube (MWNT) heterojunction arrays were synthesized and immobilized on Si(0 0 1) substrate as photocatalysts for inactivation of Escherichia coli bacteria. The vertically aligned MWNT arrays were grown on ∼5 nm Ni thin film deposited on the Si by using plasma enhanced chemical vapor deposition at 650 °C. Then, the MWNTs were coated by TiO2 using dip-coating sol-gel method. Post annealing of the TiO2/MWNTs at 400 °C resulted in crystallization of the TiO2 coating and formation of Ti-C and Ti-O-C carbonaceous bonds at the heterojunction. The visible light-induced photoinactivation of the bacteria increased from MWNTs to TiO2 to TiO2/MWNTs, in which the bacteria could...
Study of surface plasmon resonance of Cu@Cu2O core-shell nanoparticles by Mie theory
, Article Journal of Physics D: Applied Physics ; Volume 42, Issue 1 , 2009 ; 00223727 (ISSN) ; Vesaghi, M. A ; Shafiekhani, A ; Sharif University of Technology
2009
Abstract
Cu@Cu2O core-shell nanoparticles on a-C : H thin films are prepared by co-deposition of RF-sputtering and RF-PECVD. Samples with different copper concentrations are grown. The copper content of films increases with reduction in initial pressure and rises with increasing RF power. When the Cu/C ratio reaches 0.5, the surface plasmon resonance (SPR) peak that is a signature of the formation of Cu nanoparticles appears in visible spectra of these films. X-ray photoelectron spectroscopy (XPS) characterization indicates that the surface of the copper nanoparticles oxidizes when they are exposed to air. The results are indicative that the shell of the nanoparticle is mainly the Cu 2O phase that is...
Comprehensive simulation of the effects of process conditions on plasma enhanced chemical vapor deposition of silicon nitride
, Article Semiconductor Science and Technology ; Volume 23, Issue 9 , 22 August , 2008 ; 02681242 (ISSN) ; Ilati, H ; Rashidian, B ; Sharif University of Technology
2008
Abstract
A numerical model for the deposition of silicon nitride using silane and ammonia mixture in a radio frequency plasma reactor has been developed. Plasma enhanced chemical vapor deposition process is simulated by combined analysis for the glow discharge, fluid flow and chemical reactions. The main goal is to investigate the effect of variations of the process parameters on the deposition rate, and uniformity of the resulting layer. The approach used is based on the theoretical partial differential equation models, without any empirical approximation of the critical data being used. Owing to the fact that the relevant equations are highly nonlinear, the discretization method is of great...
Morphology, optical and electrical properties of Cu-Ni nanoparticles in a-C:H prepared by co-deposition of RF-sputtering and RF-PECVD
, Article Applied Surface Science ; Volume 258, Issue 2 , 2011 , Pages 727-731 ; 01694332 (ISSN) ; Vesaghi, M. A ; Gelali, A ; Zahrabi, H ; Solaymani, S ; Sharif University of Technology
Abstract
We report optical and electrical properties of Cu-Ni nanoparticles in hydrogenated amorphous carbon (Cu-Ni NPs @ a-C:H) with different surface morphology. Ni NPs with layer thicknesses of 5, 10 and 15 nm over Cu NPs @ a-C:H were prepared by co-deposition of RF-sputtering and RF-Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) from acetylene gas and Cu and Ni targets. A nonmetal-metal transition was observed as the thickness of Ni over layer increases. The surface morphology of the sample was described by a two dimensional (2D) Gaussian self-affine fractal, except the sample with 10 nm thickness of Ni over layer, which is in the nonmetal-metal transition region. X-ray diffraction profile...
Mediator-less highly sensitive voltammetric detection of glutamate using glutamate dehydrogenase/vertically aligned CNTs grown on silicon substrate
, Article Biosensors and Bioelectronics ; Volume 31, Issue 1 , 2012 , Pages 110-115 ; 09565663 (ISSN) ; Shahrokhian, S ; Iraji zad, A ; Mohajerzadeh, S ; Vosoughi, M ; Darbari, S ; Sanaee, Z ; Sharif University of Technology
Abstract
A sensitive glutamate biosensor is prepared based on glutamate dehydrogenase/vertically aligned carbon nanotubes (GLDH, VACNTs). Vertically aligned carbon nanotubes were grown on a silicon substrate by direct current plasma enhanced chemical vapor deposition (DC-PECVD) method. The electrochemical behavior of the synthesized VACNTs was investigated by cyclic voltammetry and electrochemical impedance spectroscopic methods. Glutamate dehydrogenase covalently attached on tip of VACNTs. The electrochemical performance of the electrode for detection of glutamate was investigated by cyclic and differential pulse voltammetry. Differential pulse voltammetric determinations of glutamate are performed...
Optical and electrical properties of the copper-carbon nanocomposites
, Article Nanophotonics II, Strasbourg, 7 April 2008 through 9 April 2008 ; Volume 6988 , 2008 ; 0277786X (ISSN); 9780819471864 (ISBN) ; Vesaghi, M. A ; Shafiekhani, A ; Ahmadi, M ; Sharif University of Technology
2008
Abstract
We prepared copper-carbon nanocomposite films by co-deposition of RF-Sputtering and RF-PECVD methods at room temperature. These films contain different copper concentration and different size of copper nanoparticles. The copper content of these films was obtained from Rutherford Back Scattering (RBS) analyze. We studied electrical resistivity of samples versus copper content. A metal-nonmetal transition was observed by decreasing of copper content in these films. The electrical conductivity of dielectric and metallic samples was explained by tunneling and percolation models respectively. In the percolation threshold conduction results from two mechanisms: percolation and tunneling. In the...