Analysis of New Opotoelectronic Device for Detection of Heavy Metals in Corroded Soils

Author(s):  
Gustavo Lopez Badilla ◽  
Juan Manuel Terrazas Gaynor

This study was made to design and an analysis the purpose of novel optoelectronic sensor, with three steps, being the first the use of MatLab software to simulate with a mathematical equation, the operation of the sensor as the electrical conductivity. Other step, was the evaluations with Wein2k using the Density of States (DOS) Theory, as a computational system of the physicochemical, to analyze different materials used, to fabricate the novel sensor, being the material proposed the Gallium Nitride (GaN), in according to the electrical conductivity, and was obtained, to fabricate this type of material with the Chemical Vapor Deposition (CVD) and then was made some evaluations to validate this material. Also was made a microanalysis with the Scanning Electron Microscopy (SEM) to evaluate the metallic surfaces of the electrical connections at micro scale.

2005 ◽  
Vol 17 (26) ◽  
pp. 6713-6718 ◽  
Author(s):  
Taek S. Yang ◽  
Ki-Seok An ◽  
Eun-Joo Lee ◽  
Wontae Cho ◽  
Hong S. Jang ◽  
...  

1996 ◽  
Vol 424 ◽  
Author(s):  
Hong-Seok Choi ◽  
Jae-Hong Jun ◽  
Keun-Ho Jang ◽  
Min-Koo Han

AbstractThe material properties of laser-annealed a-Si:Nx films were investigated. The a-Si:Nx films for laser-annealing were deposited by rf plasma enhanced chemical vapor deposition (PECVD) with NH3 and SiH4 gas mixtures. At the 0.35 of NH3/SiH4 ratio, the optical band-gap was abruptly increased to 2.82 eV from 2.05 eV by laser-annealing which indicates that Si-N bonding comes to be notable at that ratio. The electrical conductivity showed the maximum value of 4× 10-6 S/cm at the 0.11 of NH3/SiH4 ratio where the grain growth and the increase of Si-N bonding are optimized for the enhancement of electrical conductivity. The σP/σD ratio which is related to the defects states for photo generation centers was decreased with increasing NH 3/SiH 4 ratio. Our experimental data showed that the optical band gap and electrical conductivity of laserannealed a-Si:Nx films were dominantly affected by the NH3/SiH4 ratio at the 250 mJ/cm2 of laser-annealing energy density.


2013 ◽  
Vol 205-206 ◽  
pp. 284-289 ◽  
Author(s):  
David Lysáček ◽  
Petr Kostelník ◽  
Petr Pánek

We report on a novel method of low pressure chemical vapor deposition of polycrystalline silicon layers used for external gettering in silicon substrate for semiconductor applications. The proposed method allowed us to produce layers of polycrystalline silicon with pre-determined residual stress. The method is based on the deposition of a multilayer system formed by two layers. The first layer is intentionally designed to have tensile stress while the second layer has compressive stress. Opposite sign of the residual stresses of the individual layers enables to pre-determine the residual stress of the gettering stack. We used scanning electron microscopy for structural characterization of the layers and intentional contamination for demonstration of the gettering properties. Residual stress of the layers was calculated from the wafer curvature.


1990 ◽  
Vol 5 (6) ◽  
pp. 1169-1175 ◽  
Author(s):  
A. D. Berry ◽  
R. T. Holm ◽  
M. Fatemi ◽  
D. K. Gaskill

Films containing the metals copper, yttrium, calcium, strontium, barium, and bismuth were grown by organometallic chemical vapor deposition (OMCVD). Depositions were carried out at atmospheric pressure in an oxygen-rich environment using metal beta-diketonates and triphenylbismuth. The films were characterized by Auger electron spectroscopy, Nomarski and scanning electron microscopy, and x-ray diffraction. The results show that films containing yttrium consisted of Y2O3 with a small amount of carbidic carbon, those with copper and bismuth were mixtures of oxides with no detectable carbon, and those with calcium, strontium, and barium contained carbonates. Use of a partially fluorinated barium beta-diketonate gave films of BaF2 with small amounts of BaCO3.


1988 ◽  
Vol 3 (6) ◽  
pp. 1397-1403 ◽  
Author(s):  
Duane E. Meyer ◽  
Natale J. Ianno ◽  
John A. Woollam ◽  
A. B. Swartzlander ◽  
A. J. Nelson

A system has been designed and constructed to produce diamond particles by inductively coupled radio-frequency, plasma-assisted chemical vapor deposition. This is a low-pressure, low-temperature process used in an attempt to deposit diamond on substrates of glass, quartz, silicon, nickel, and boron nitride. Several deposition parameters have been varied including substrate temperature, gas concentration, gas pressure, total gas flow rate, rf input power, and deposition time. Analytical methods employed to determine composition and structure of the deposits include scanning electron microscopy, absorption spectroscopy, scanning Auger microprobe spectroscopy, and Raman spectroscopy. Analysis indicates that particles having a thin graphite surface, as well as diamond particles with no surface coatings, have been deposited. Deposits on quartz have exhibited optical bandgaps as high as 4 5 eV. Scanning electron microscopy analysis shows that particles are deposited on a pedestal which Auger spectroscopy indicates to be graphite. This is a phenomenon that has not been previously reported in the literature.


2006 ◽  
Vol 317-318 ◽  
pp. 665-668 ◽  
Author(s):  
Seung Hwa Yoo ◽  
H.J. Wang ◽  
Sung Tag Oh ◽  
Sung Goon Kang ◽  
Yong Ho Choa

CNTs/Fe/Al2O3 nanocomposites were prepared by thermal CVD and SPS methods. The dispersion of CNTs in the Fe/Al2O3 matrix were controlled by an attrition milling process. FESEM analysis revealed that the CNTs of 5 vol.% were homogeneously dispersed in the Fe/Al2O3. The effects of CNTs dispersion on the mechanical and electrical properties of the specimens were investigated. Fracture strength and electrical conductivity of 5 vol.% CNTs/Fe/Al2O3 specimen were measured at 641 MPa and 2.93 10-11 mS/m, whereas that of a 20 vol.% CNTs/Fe/Al2O3 specimen were 208 MPa and 8.46 10-7 mS/m, respectively. In comparison with an Al2O3 monolith, the specimen with 5 vol.% CNTs showed enhanced fracture strength and increased electrical conductivity.


2011 ◽  
Vol 339 ◽  
pp. 3-6
Author(s):  
Chun Hua Xu ◽  
Kelvin Leung ◽  
Charles Surya

ZnO nanowires were grown on Au-coated GaN layer on c-plane sapphire by chemical vapor deposition (CVD). As-prepared ZnO oxides were characterized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results show that the growth of ZnO nanowires strongly depends on the location of GaN/sapphire substrates. The diameters of the resulting nanowires were in the range 60 nm with typical length about 10μm. The formation of ZnO nanowires with different morphologies at various positions of the substrate is explained by the mechanisms of vapor-solid and vapor-liquid-solid, respectively.


1989 ◽  
Vol 168 ◽  
Author(s):  
Paul D. Stupik ◽  
Linda K. Cheatham ◽  
John J. Graham ◽  
Andrew R. Barron

AbstractChemical vapor deposition from (MeCp)2Nb(allyl) at atmospheric pressure yields niobium carbide films at temperatures as low as 300°C. X-ray photoelectron spectroscopy (XPS) studies indicate that the bulk films contain a carbide phase and a nearly stoichiometric ratio of niobium to carbon. The morphology of the films has been examined by scanning electron microscopy (SEM).


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