Search results for: successive deposition technique

Authors: Kwang-Ho Kim, Kwan-Hong Min, Pyungwoo Jang, Chisup Jung, Kyu Seomoon

Abstract:

By restricting the dimensions of silicon to less than Bohr radius of bulk crystalline silicon (∼5 nm), quantum confinement causes its effective bandgap to increase. Therefore, silicon quantum wells (QWs) using these quantum phenomena could be a good candidate to achieve high performance silicon solar cells. The Al2O3/Si QW structures were fabricated by using the successive deposition technique, as a quantum confinement device to increase the effective energy bandgap and passivation effect in Si surface for the 3rd generation solar cell applications. In Si/Al2O3 QWs, the thicknesses of Si layers and Al2O3 layers were varied between 1 to 5 nm, respectively. The roughness of deposited Si on Al2O3 was less than 4 Å in the thickness of 2 nm. By using the Al2O3/Si QW structures on Si surfaces, the lifetime measured by u-PCD technique increased as a result of passivated surface effects. The discussion about the other properties such as electrical and optical properties of the QWs structures as well as the fabricated solar cells will be presented in this paper.

Keywords: Al2O3/Si quantum well, quantum confinement, solar cells, third generation, successive deposition technique

Procedia PDF Downloads 303

Authors: Jeff Letcher, Dennis Tierney, Haider Raad

Abstract:

Antennas are devices for transmitting and/or receiving signals which make them a necessary component of any wireless system. In this paper, a thermal deposition technique is utilized as a method to fabricate antenna structures on substrates. Thin-film deposition is achieved by evaporating a source material (metals in our case) in a vacuum which allows vapor particles to travel directly to the target substrate which is encased with a mask that outlines the desired structure. The material then condenses back to solid state. This method is used in comparison to screen printing, chemical etching, and ink jet printing to indicate advantages and disadvantages to the method. The antenna created undergoes various testing of frequency ranges, conductivity, and a series of flexing to indicate the effectiveness of the thermal deposition technique. A single band antenna that is operated at 2.45 GHz intended for wearable and flexible applications was successfully fabricated through this method and tested. It is concluded that thermal deposition presents a feasible technique of producing such antennas.

Keywords: thermal deposition, wearable antennas, bluetooth technology, flexible electronics

Procedia PDF Downloads 251

Authors: Elena A. Outkina, Marina V. Meledina, Aliaksandr A. Khodin

Abstract:

Nanostructured thin films of SnSₓ, Cu₂ZnSnS₄ (CZTS) semiconductors were fabricated by chemical processing to produce thin-film photoactive layers for photocells as a prospective lowest-cost and environment-friendly alternative to Si, Cu(In, Ga)Se₂, and other traditional solar cells materials. To produce SnSₓ layers, the modified successive ionic layer adsorption and reaction (SILAR) technique were investigated, including successive cyclic dipping into Na₂S solution and SnCl₂, NaCl, triethanolamine solution. To fabricate CZTS layers, the cyclic dipping into CuSO₄ with ZnSO₄, SnCl₂, and Na₂S solutions was used with intermediate rinsing in distilled water. The nano-template aluminum/alumina substrate was used to control deposition processes. Micromorphology and optical characteristics of the fabricated layers have been investigated. Analysis of 2D-like layers deposition features using nano-template substrate is presented, including the effect of nanotips in a template on surface charge redistribution and transport.

Keywords: kesterite, nanotemplate, SILAR, solar cell, tin sulphide

Procedia PDF Downloads 107

Authors: Anis A. Ansari, M. Kamil

Abstract:

The development of 3D printing technology has allowed the manufacturing industry to create parts with a high degree of automation, increased design freedom, and improved mechanical performance. Fused deposition modelling (FDM) is a 3D printing technique in which successive layers of thermoplastic polymer are deposited and controlled to create a three-dimensional product. In this study, process parameters such as nozzle temperature and printing speed were chosen to investigate their effects on hardness properties. 3D printed specimens were fabricated by an FDM 3D printer from Polylactic acid (PLA) polymer. After analysis, it was observed that the hardness property is much influenced by print speed and nozzle temperature parameters. Maximum hardness was achieved at higher print speed which indicates that the Shore D hardness is directly proportional to the print speed. Moreover, at higher print speed, it has no significant dependence on the nozzle temperature. Hardness is also influenced by nozzle temperature, though to a lesser extent. The hardness slightly lowers when the nozzle temperature is raised from 190 to 210 oC, but due to improved bonding between each raster, a further rise in temperature increases the hardness property.

Keywords: 3D printing, fused deposition modeling (FDM), polylactic acid (PLA), print speed, nozzle temperature, hardness property

Procedia PDF Downloads 60

Authors: Sima Shakoorjavan, Dawid Stawski, Somaye Akbari

Abstract:

In this study, the adsorption-desorption behavior of poly(amidoamine) (PAMAM) as a polycation and poly (acrylic acid) (PAA) as a polyanion deposited on aminolyzed-PLA nonwoven through layer-by-layer technique (lbl) was studied. The adsorption-desorption behavior was monitored by UV adsorbance spectroscopy and turbidity tests of the waste polyelectrolytes after each deposition. Also, the drying between each deposition step was performed to study the effect of drying on adsorption-desorption behavior. According to UV adsorbance spectroscopy of the waste polyelectrolyte after each deposition, it was revealed that drying has a great effect on the deposition behavior of the next layer. Regarding the deposition of the second layer, drying caused more desorption and removal of the previously deposited layer since the turbidity and the absorbance of the waste increased in comparison to pure polyelectrolyte. To deposit the third layer, the same scenario occurred and drying caused more removal of the previously deposited layer. However, the deposition of the fourth layer drying after the deposition of the third layer did not affect the adsorption-desorption behavior. Since the adsorbance and turbidity of the samples that were dried and those that were not dried were the same. As a result, it seemed that deposition of the fourth layer could be the starting point where lbl reached its constant state. The decrease in adsorbance and remaining turbidity of the waste same as a pure polyelectrolyte can indicate that most portion of the polyelectrolyte was adsorbed onto the substrate rather than complex formation in the bath as the subsequence of the previous layer removal.

Keywords: Adsorption-desorption behavior, lbl technique, poly(amidoamine), poly (acrylic acid), weak polyelectrolytes

Procedia PDF Downloads 21

Authors: Prashanta Dhoj Adhikari

Abstract:

We report the introduction of the active surface functionalization group on chemical vapor deposition (CVD) grown graphene film by wet deposition method. The activity of surface functionalized group was tested with surface modified carbon nanotubes (CNTs) and found that both materials were amalgamated by chemical bonding. The introduction of functional group on the graphene film surface and its vigorous role to bind CNTs with the present technique could provide an efficient, novel route to device fabrication.

Keywords: chemical vapor deposition, graphene film, surface functionalization

Procedia PDF Downloads 434

Authors: Z. Mahmood, F. U. Babar, S. Naz, H. U. Rehman

Abstract:

Cadmium Sulphide (CdS) was deposited on a Tec 15 glass substrate with the help of CBD (chemical bath deposition process) and then cadmium telluride CdTe was deposited on CdS with the help of CSS (closed spaced sublimation technique) for the construction of a solar cell. The thicknesses of all the deposited materials were measured with the help of Ellipsometry. The IV graphs were drawn in order to observe the current voltage output. The efficiency of the cell was graphed with the fill factor as well (graphs not given here). The efficiency came out to be approximately 16.5 % and the CIGS (copper-indium–gallium-selenide) maximum efficiency is 20 %. The efficiency of a solar cell can further be enhanced by adapting quality materials, good experimental devices and proper procedures. The grain size was analyzed with the help of scanning electron microscope using RBS (Rutherford backscattering spectroscopy).

Keywords: Chemical Bath Deposition Technique (CBD), cadmium sulphide (CdS), CdTe, CSS (Closed Space Sublimation)

Procedia PDF Downloads 326

Authors: Nouf Alharbi

Abstract:

The electrospray deposition technique became an important method that enables fragile, nonvolatile molecules to be deposited in situ in high vacuum environments. Furthermore, it is considered one of the ways to close the gap between basic surface science and molecular engineering, which represents a gradual change in the range of scientist research. Also, this paper talked about one of the most important techniques that have been developed and aimed for helping to further develop and characterize the electrospray by providing data collected using an image charge detection instrument. Image charge detection mass spectrometry (CDMS) is used to measure speed and charge distributions of the molecular ions. As well as, some data has been included using SIMION simulation to simulate the energies and masses of the molecular ions through the system in order to refine the mass-selection process.

Keywords: charge, deposition, electrospray, image, ions, molecules, SIMION

Procedia PDF Downloads 107

Authors: Igori Wallace

Abstract:

Zinc oxide (ZnO) nanowires with hexagonal structure were successfully synthesized by the chemical bath deposition technique. The obtained nanowires were characterized by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The SEM micrographs revealed the morphology of ZnO nanowires with the diameter between 170.3 and 481nm and showed that the normal pH of the bath solution, 8.1 is the optimized value to form ZnO nanowires with the hexagonal shape. The compositional (EDX) analysis revealed the elemental compositions of samples and confirmed the presence of Zn and O.

Keywords: crystallite, chemical bath deposition technique, hexagonal, morphology, nanowire

Procedia PDF Downloads 279

Authors: S. Suman, G. N. Singh

Abstract:

This research work is an effort to analyse the consequences of scrambled response technique to estimate the current population mean in two-occasion successive sampling when the characteristic of interest is sensitive in nature. The generalized estimation procedures have been proposed using sensitive auxiliary variables under additive and multiplicative scramble models. The properties of resultant estimators have been deeply examined. Simulation, as well as empirical studies, are carried out to evaluate the performances of the proposed estimators with respect to other competent estimators. The results of our studies suggest that the proposed estimation procedures are highly effective under the presence of non-response situation. The result of this study also suggests that additive scrambled response model is a better choice in the perspective of cost of the survey and privacy of the respondents.

Keywords: scrambled response, sensitive characteristic, successive sampling, optimum replacement strategy

Procedia PDF Downloads 147

Authors: Xiaodong Gao, Pingchuan Dong, Qichao Gao

Abstract:

There has been lots of published work focused on asphaltene deposited on the smooth pipe under steady conditions, while particle deposition on the blockage wellbores under transient conditions has not been well elucidated. This work attempts to predict the deposition rate of asphaltene particles in blockage tube through CFD simulation. The Euler-Lagrange equation has been applied during the flow of crude oil and asphaltene particles. The net gravitational force, virtual mass, pressure gradient, saffman lift, and drag forces are incorporated in the simulations process. Validation of CFD simulation results is compared to the benchmark experiments from the previous literature. Furthermore, the effect of blockage location, blockage length, and blockage thickness on deposition rate are also analyzed. The simulation results indicate that the maximum deposition rate of asphaltene occurs in the blocked tube section, and the greater the deposition thickness, the greater the deposition rate. Moreover, the deposition amount and maximum deposition rate along the length of the tube have the same trend. Results of this study are in the ability to better understand the deposition of asphaltene particles in production and help achieve to deal with the asphaltene challenges.

Keywords: asphaltene deposition rate, blockage length, blockage thickness, blockage diameter, transient condition

Procedia PDF Downloads 165

Authors: S. Zhuiykov, Zh. Hai, H. Xu, C. Xue

Abstract:

Unique and distinctive properties could be obtained on such two-dimensional (2D) semiconductor as tungsten trioxide (WO₃) when the reduction from multi-layer to one fundamental layer thickness takes place. This transition without damaging single-layer on a large spatial resolution remained elusive until the atomic layer deposition (ALD) technique was utilized. Here we report the ALD-enabled atomic-layer-precision development of a single layer WO₃ with thickness of 0.77±0.07 nm on a large spatial resolution by using (^tBuN)₂W(NMe₂)₂ as tungsten precursor and H₂O as oxygen precursor, without affecting the underlying SiO₂/Si substrate. Versatility of ALD is in tuning recipe in order to achieve the complete WO₃ with desired number of WO₃ layers including monolayer. Governed by self-limiting surface reactions, the ALD-enabled approach is versatile, scalable and applicable for a broader range of 2D semiconductors and various device applications.

Keywords: Atomic Layer Deposition (ALD), tungsten oxide, WO₃, two-dimensional semiconductors, single fundamental layer

Procedia PDF Downloads 212

Authors: P. Kanakasabapathy, S. Radhika

Abstract:

In the competitive electricity market environment, the profit of the pumped-storage plant in the energy market can be maximized by operating it as a generator, when market clearing price is high and as a pump, to pump water from lower reservoir to upper reservoir, when the price is low. An optimal self-scheduling plan has been developed for a pumped-storage plant, carried out on weekly basis in order to maximize the profit of the plant, keeping into account of all the major uncertainties such as the sudden ancillary service delivery request and the price forecasting errors. For a pumped storage power plant to operate in a real time market successive self-scheduling has to be done by considering the forecast of the day-ahead market and the modified reservoir storage due to the ancillary service request of the previous day. Sliding Window Technique has been used for successive self-scheduling to ensure profit for the plant.

Keywords: ancillary services, BPSO, power system economics, self-scheduling, sliding window technique

Procedia PDF Downloads 373

Authors: Renu Kumari, Jyotsna Dutta Majumdar

Abstract:

In the present study, composite coating consisting of hydroxyapatite (HA) + 50 wt% TiO2 has been developed on Ti-6Al-4V substrate by plasma spray deposition technique. Followed by plasma spray deposition, detailed surface roughness and microstructural characterization were carried out by using optical profilometer and scanning electron microscopy (SEM), respectively. The composition and phase analysis were carried out by energy-dispersive X-ray spectroscopy analysis, and X-ray diffraction (XRD) technique, respectively. The bio-activity behavior of the uncoated and coated samples was also compared by dipping test in Hank’s solution. The average surface roughness of the coating was 10 µm (as compared to 0.5 µm of as-received Ti-6Al-4V substrate) with the presence of porosities. The microstructure of the coating was found to be continuous with the presence of solidified splats. A detailed XRD analysis shows phase transformation of TiO2 from anatase to rutile, decomposition of hydroxyapatite, and formation of CaTiO3 phase. Standard dipping test confirmed a faster kinetics of deposition of calcium phosphate in the coated HA+50% wt.% TiO2 surface as compared to the as-received substrate.

Keywords: titanium, plasma spraying, microstructure, bio-activity, TiO2, hydroxyapatite

Procedia PDF Downloads 284

Authors: N. Dahbi, D. E. Arafah

Abstract:

Cd1−xZnxS thins films have been fabricated from ZnS/CdS/ZnS multilayer thin film systems, by using the vacuum deposition method; the Rutherford back-scattering (RBS) technique have been applied in order to determine the: structure, composition, depth profile, and stoichiometric of these films. The influence of the chemical and heat treatments on the produced films also have been investigated; the RBS spectra of the films showed that homogenous Cd1−xZnxS can be synthesized with x=0.45.

Keywords: Cd1−xZnxS, chemical treatment, depth profile, heat treatment, RBS, RUMP simulation, thin film, vacuum deposition, ZnS/CdS/ZnS

Procedia PDF Downloads 195

Authors: M. M. Moharam, E. M. Elsayed, M. M. Rashad

Abstract:

Single phase Cu₂O films have been prepared via an electrodeposition technique onto ITO glass substrates at room temperature. Likewise, Cu₂O films were deposited using a potentiostatic process from an alkaline electrolyte containing copper (II) nitrate and 1M sodium citrate. Single phase Cu₂O films were electrodeposited at a cathodic deposition potential of 500mV for a reaction period of 90 min, and pH of 12 to yield a film thickness of 0.49 µm. The mechanism for nucleation of Cu₂O films was found to vary with deposition potential. Applying the Scharifker and Hills model at -500 and -600 mV to describe the mechanism of nucleation for the electrochemical reaction, the nucleation mechanism consisted of a mix between instantaneous and progressive growth mechanisms at -500 mV, while above -600 mV the growth mechanism was instantaneous. Using deposition times from 30 to 90 min at -500 mV deposition potential, pure Cu2O films with different microstructures were electrodeposited. Changing the deposition time from 30 to 90 min varied the microstructure from cubic to more complex polyhedra. The transmittance of electrodeposited Cu₂O films ranged from 20-70% in visible range, and samples exhibited a 2.4 eV band gap. The electrical resistivity for electrodeposited Cu₂O films was found to decrease with increasing deposition time from 0.854 x 105 Ω-cm at 30 min to 0.221 x 105 Ω-cm at 90 min without any thermal treatment following the electrodeposition process.

Keywords: Cu₂O, electrodeposition, film thickness, characterization, optical properties

Procedia PDF Downloads 180

Authors: Bing Shi, Raymond A. Conley, Jun Qian, Xianbo Shi, Steve Heald, Lahsen Assoufid

Abstract:

A pair of Kirkpatrick-Baez (KB) mirrors were designed and fabricated for experiments within a hard x-ray energy range lower than 20 kev at beamline 20-ID in a synchrotron radiation facility, Advanced Photon Source (APS). The KB mirrors were deposited with Rhodium thin films using a customized designed and self-built magnetron sputtering system. The purpose of these mirrors is to focus the x-ray beam down to 1 micron. This is the first pair of Rhodium-coated KB mirrors with elliptical shape that was fabricated using the profile coating technique. The profile coating technique is to coat the substrate with designed shape using masks during the deposition. The mirrors were equipped at the beamline and achieved the designed focusing requirement. The details of the mirror design, the fabrication process, and the customized magnetron sputtering deposition system will be discussed.

Keywords: magnetron-sputtering deposition, focusing optics, x-ray, rhodium thin film

Procedia PDF Downloads 338

Authors: Esam I. Jassim

Abstract:

The main aim of this paper is to demonstrate the prediction of the model capability of predicting the nucleation process, the growth rate, and the deposition potential of second phase particles in gas flowlines. The primary objective of the research is to predict the risk hazards involved in the marine transportation of compressed natural gas. However, the proposed model can be equally used for other applications including production and transportation of natural gas in any high-pressure flow-line. The proposed model employs the following three main components to approach the problem: computational fluid dynamics (CFD) technique is used to configure the flow field; the nucleation model is developed and incorporated in the simulation to predict the incipient hydrate particles size and growth rate; and the deposition of the gas/particle flow is proposed using the concept of the particle deposition velocity. These components are integrated in a comprehended model to locate the hydrate deposition in natural gas flowlines. The present research is prepared to foresee the deposition location of solid particles that could occur in a real application in Compressed Natural Gas loading and offloading. A pipeline with 120 m length and different sizes carried a natural gas is taken in the study. The location of particle deposition formed as a result of restriction is determined based on the procedure mentioned earlier and the effect of water content and downstream pressure is studied. The critical flow speed that prevents such particle to accumulate in the certain pipe length is also addressed.

Keywords: hydrate deposition, compressed natural gas, marine transportation, oceanography

Procedia PDF Downloads 446

Authors: F. Stephen Joe, V. Sathya Narayanan, V. R. Sanal Kumar

Abstract:

A comprehensive review of the literature on photovoltaic cells has been carried out for exploring the better options for cost efficient technologies for future solar cell applications. Literature review reveals that the Bulk Heterojunction (BHJ) Polymer Solar cells offer special opportunities as renewable energy resources. It is evident from the previous studies that the device fabricated with TiOx layer shows better power conversion efficiency than that of the device without TiOx layer. In this paper, authors designed a controlled BHJ solar cell using a modified organic vapor spray deposition technique facilitated with a vertical-moving gun named as 'Stephen Joe Technique' for getting a desirable surface pattern over the substrate to improving its efficiency over the years for industrial applications. We comprehended that the efficient processing and the interface engineering of these solar cells could increase the efficiency up to 5-10 %.

Keywords: BHJ polymer solar cell, photovoltaic cell, solar cell, Stephen Joe technique

Procedia PDF Downloads 513

Authors: Damian A. Mooney, Michael T. P. Mc Cann, J. M. Don MacElroy, Olli Antson, Denis P. Dowling

Abstract:

Atmospheric pressure plasma liquid deposition (APPLD) is a novel technology used for the deposition of thin films via the injection of a reactive liquid precursor into a high-energy discharge plasma at ambient pressure. In this work, APPLD, utilising a TEOS precursor, was employed to produce asymmetric membranes consisting of a thin (100 nm) layer of deposited silica on a microporous silica support in order to assess their suitability for high temperature gas separation applications. He and N₂ gas permeability measurements were made for each of the fabricated membranes and a maximum ideal He/N₂ selectivity of 66 was observed at room temperature. He, N₂ and CO2 gas permeances were also measured at the elevated temperature of 673K and ideal He/N₂ and CO₂/N₂ selectivities of 300 and 7.4, respectively, were observed. The results suggest that this plasma-based deposition technique can be a viable method for the manufacture of membranes for the efficient separation of high temperature, post-combustion gases, including that of CO₂/N₂ where the constituent gases differ in size by fractions of an Ångstrom.

Keywords: asymmetric membrane, CO₂ separation, high temperature, plasma deposition, thin films

Procedia PDF Downloads 279

Authors: Odai Ibrahim Mohammed Al Balasmeh, Tapas Karmaker, Richa Babbar

Abstract:

In this study, the reservoir capacity and sediment deposition were estimated using remote sensing data. The satellite images were synchronized with water level and storage capacity to find out the change in sediment deposition due to soil erosion and transport by streamflow. The water bodies spread area was estimated using vegetation indices, e.g., normalize differences vegetation index (NDVI) and normalize differences water index (NDWI). The 3D reservoir bathymetry was modeled by integrated water level, storage capacity, and area. From the models of different time span, the change in reservoir storage capacity was estimated. Another reservoir with known water level, storage capacity, area, and sediment deposition was used to validate the estimation technique. The t-test was used to assess the results between observed and estimated reservoir capacity and sediment deposition.

Keywords: satellite data, normalize differences vegetation index, NDVI, normalize differences water index, NDWI, reservoir capacity, sedimentation, t-test hypothesis

Procedia PDF Downloads 136

Authors: Xiuguo Zhao, He Li, Alireza Yazdani, Xiaoning Zheng, Xinxi Xu

Abstract:

Wound infected poses a serious threat to the surgery on the patient during the process of surgery. Understanding the bacteria-carrying particles (BCPs) transportation and deposition in the open surgical wound model play essential role in protecting wound against being infected. Therefore BCPs transportation and deposition in the surgical wound model were investigated using force-coupling method (FCM) based computational fluid dynamics. The BCPs deposition in the wound was strongly associated with BCPs diameter and concentration. The results showed that the rise on the BCPs deposition was increasing not only with the increase of BCPs diameters but also with the increase of the BCPs concentration. BCPs deposition morphology was impacted by the combination of size distribution, airflow patterns and model geometry. The deposition morphology exhibited the characteristic with BCPs deposition on the sidewall in wound model and no BCPs deposition on the bottom of the wound model mainly because the airflow movement in one direction from up to down and then side created by laminar system constructing airflow patterns and then made BCPs hard deposit in the bottom of the wound model due to wound geometry limit. It was also observed that inertial impact becomes a main mechanism of the BCPs deposition. This work may contribute to next study in BCPs deposition limit, as well as wound infected estimation in surgical-site infections.

Keywords: BCPs deposition, computational fluid dynamics, force-coupling method (FCM), numerical simulation, open surgical wound model

Procedia PDF Downloads 262

Authors: Yusuf S. Dambatta, Ahmed A. D. Sarhan

Abstract:

Fused deposition modelling (FDM) is one of the most prominent rapid prototyping (RP) technologies which is being used to efficiently fabricate CAD 3D geometric models. However, the process is coupled with many drawbacks, of which the surface quality of the manufactured RP parts is among. Hence, studies relating to improving the surface roughness have been a key issue in the field of RP research. In this work, a technique of modelling the surface roughness in FDM is presented. Using experimentally measured surface roughness response of the FDM parts, an ANFIS prediction model was developed to obtain the surface roughness in the FDM parts using the main critical process parameters that affects the surface quality. The ANFIS model was validated and compared with experimental test results.

Keywords: surface roughness, fused deposition modelling (FDM), adaptive neuro fuzzy inference system (ANFIS), orientation

Procedia PDF Downloads 416

Authors: Camilla G. Goncalves, Benedito Christ, Walter Miyakawa, Antonio J. Abdalla

Abstract:

This work aims to investigate the properties and microstructure of diamond-like carbon film deposited by pulsed laser deposition by ablation of a graphite target in a vacuum chamber on a steel substrate. The equipment was mounted to provide one laser beam. The target of high purity graphite and the steel substrate were polished. The mechanical and tribological properties of the film were characterized using Raman spectroscopy, nanoindentation test, scratch test, roughness profile, tribometer, optical microscopy and SEM images. It was concluded that the pulsed laser deposition (PLD) technique associated with the low-pressure chamber and a graphite target provides a good fraction of sp3 bonding, that the process variable as surface polishing and laser parameter have great influence in tribological properties and in adherence tests performance. The optical microscopy images are efficient to identify the metallurgical bond.

Keywords: characterization, DLC, mechanical properties, pulsed laser deposition

Procedia PDF Downloads 126

Authors: Jin-Woo Park, Sung-Soo Lee, Nong-Moon Hwang

Abstract:

The generation of charged nanoparticles in the gas phase during the Chemical Vapor Deposition (CVD) process has been frequently reported with their subsequent deposition into films and nanostructures in many systems such as carbon, silicon and zinc oxide. The microstructure evolution of films and nanostructures is closely related with the size distribution of charged nanoparticles. To confirm the generation of charged nanoparticles during GaN, the generation of GaN charged nanoparticles was examined in an atmospheric pressure CVD process using a Differential Mobility Analyser (DMA) combined with a Faraday Cup Electrometer (FCE). It was confirmed that GaN charged nanoparticles were generated under the condition where GaN nanostructures were synthesized on the bare and Au-coated Si substrates. In addition, the deposition behaviour depends strongly on the charge transfer rate of metal substrates. On the metal substrates of a lower CTR such as Mo, the deposition rate of GaN was much lower than on those of a higher CTR such as Fe. GaN nanowires tend to grow on the substrates of a lower CTR whereas GaN thin films tend to be deposited on the substrates of a higher CTR.

Keywords: chemical vapour deposition, charged cluster model, generation of charged nanoparticles, deposition behaviour, nanostructures, gan, charged transfer rate

Procedia PDF Downloads 400

Authors: Ravish K. Jain, Jatinder Kaur, Shaira Arora, Arun Kumar, Amit K. Chawla, Atul Khanna

Abstract:

Surface-dependent properties such as hydrophobicity can be modified significantly by oblique angle deposition technique. Bi thin films were studied for their hydrophobic nature. The effects of oblique angle deposition on structural, surface morphology, electrical and wettability properties of Bi thin films have been studied and a comparison of these physical properties of normally deposited and obliquely deposited Bi films has been carried out in this study. X-ray diffraction studies found that films have highly oriented hexagonal crystal structure and crystallite size is smaller for obliquely deposited (70 nm) film as compared to that of the normally deposited film (111 nm). Raman spectra of the films consist of peaks corresponding to E_g and A_1g first-order Raman modes of bismuth. The atomic force and scanning electron microscopy studies show that the surface roughness of obliquely deposited film is higher as compared to that of normally deposited film. Contact angle measurements revealed that both films are strongly hydrophobic in nature with the contact angles of 105ᵒ and 119ᵒ for normally and obliquely deposited films respectively. Oblique angle deposition enhances the hydrophobicity of the film. The electrical conductivity of the film is significantly reduced by oblique angle deposition. The activation energies for electrical conduction were determined by four-probe measurements and are 0.016 eV and 0.018 eV for normally and obliquely deposited films respectively.

Keywords: bi thin films, hydrophobicity, oblique angle deposition, surface morphology

Procedia PDF Downloads 222

Authors: Zafar Mahmood, Fahimullah Babar, Surriyia Naz, Hafiz Ur Rehman

Abstract:

Cadmium Sulphide (CdS) was deposited on a Tec 15 glass substrate with the help of CBD (chemical bath deposition process) and then cadmium telluride CdTe was deposited on CdS with the help of CSS (closed spaced sublimation technique) for the construction of a solar cell. The thicknesses of all the deposited materials were measured with the help of Elipsometry. The IV graphs were drawn in order to observe the current voltage output. The efficiency of the cell was graphed with the fill factor as well (graphs not given here).The efficiency came out to be approximately 16.5 % and the CIGS (copper- indium –gallium- selenide) maximum efficiency is 20 %.The efficiency of a solar cell can further be enhanced by adapting quality materials, good experimental devices and proper procedures. The grain size was analyzed with the help of scanning electron microscope using RBS (Rutherford backscattering spectroscopy).

Keywords: CBD, CdS, CdTe, CSS

Procedia PDF Downloads 323

Authors: Prashant Sharma, Jyotsna Dutta Majumdar

Abstract:

The present study concerns development of a composite thermal barrier coating consisting of a mixture of La2O3 and YSZ (with 8 wt.%, 32 wt.% and 50 wt.% 50% La2O3) by plasma spray deposition technique on a CoNiCrAlY based bond coat deposited on Inconel 718 substrate by high velocity oxy-fuel deposition (HVOF) technique. The addition of La2O3 in YSZ causes the formation of pyrochlore (La2Zr2O7) phase in the inter splats boundary along with the presence of LaYO3 phase. The coefficient of thermal expansion is significantly reduced from due to the evolution of different phases and structural defects in the sprayed coating. The activation energy for TGO growth under isothermal and cyclic oxidation was increased in the composite coating as compared to YSZ coating.

Keywords: plasma spraying, oxidation resistance, thermal barrier coating, microstructure, X-ray method

Procedia PDF Downloads 317

Authors: Joshua Kim Schimpf, Kyun Doo Kim, Jaseok Heo

Abstract:

In this study, the droplet behavior of under horizontal stratified flow regime for air and water flow in horizontal pipe experiments from a 0.24 m, 0.095 m, and 0.0486 m size diameter pipe are examined. The effects of gravity, pipe diameter, and turbulent diffusion on droplet deposition are considered. Models for droplet entrainment and deposition are proposed that considers developing length. Validation for experimental data dedicated from the REGARD, CEA and Williams, University of Illinois, experiment were performed using SPACE (Safety and Performance Analysis Code for Nuclear Power Plants).

Keywords: droplet, entrainment, deposition, horizontal

Procedia PDF Downloads 347

Authors: Mattea Carmen Castrovilli, Antonella Cartoni

Abstract:

Electrospray ionisation (ESI), a well-established technique widely used to produce ion beams of biomolecules in mass spectrometry (ESI-MS), can be used for ambient soft landing of enzymes on a specific substrate. In this work, we show how the ambient electrospray deposition (ESD) technique can be successfully exploited for manufacturing a promising, green-friendly electrochemical amperometric laccase-based biosensor with unprecedented reuse and storage performance. These biosensors have been manufactured by spraying a laccase solution of 2μg/μL at 20% of methanol on a commercial carbon screen printed electrode (C-SPE) using a custom ESD set-up. The laccase-based ESD biosensor has been tested against catechol compounds in the linear range 2-100 μM, with a limit of detection of 1.7 μM, without interference from cadmium, chrome, arsenic, and zinc and without any memory effects, but showing a matrix effect in lake and well water. The ESD biosensor shows enhanced performances compared to the ones fabricated with other immobilization methods, like drop-casting. Indeed, it retains 100% activity up to two months of storage at ambient conditions without any special care and working stability up to 63 measurements on the same electrode just prepared and 20 on a one-year-old electrode subjected to redeposition together with a 100% resistance to use of the same electrode in subsequent days. The ESD method is a one-step, environmentally friendly method that allows the deposition of the bio-recognition layer without using any additional chemicals. The promising results in terms of storage and working stability also obtained with the more fragile lactate oxidase enzyme suggest these improvements should be attributed to the ESD technique rather than to the bioreceptor, highlighting how the ESD could be useful in reducing pollution from disposable devices. Acknowledgment: The understanding at the molecular level of this promising biosensor by using different spectroscopies, microscopies and analytical techniques is the subject of our PRIN 2022 project ESILARANTE.

Keywords: reuse, storage performance, immobilization, electrospray deposition, biosensor, laccase, catechol detection, green chemistry

Procedia PDF Downloads 29