Physical and electrical characterization of TiO2 particles after high temperature processing and before and after ultraviolet irradiation

2014 ◽  
Vol 92 (7/8) ◽  
pp. 832-837
Author(s):  
J. Molina ◽  
C. Zúñiga ◽  
M. Moreno ◽  
W. Calleja ◽  
P. Rosales ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Uv Irradiation ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Electrical Characterization ◽  
Metal Electrode ◽  
Rutile Phase ◽  
Before And After ◽  
Diffraction Patterns

In this work, rutile-phase TiO2 particles (r-TiO2, about 360 nm in size) are embedded within a silicon oxide matrix using different concentration ratios of r-TiO2 with respect to SiO2:H2O, so that suspensions of mixed TiO2:SiO2 oxides were obtained and analyzed. These TiO2:SiO2 suspensions were deposited on previously-cleaned crystalline silicon and quartz substrates so that thin films of TiO2:SiO2 were obtained. All films were then exposed to relatively high-temperature thermal treatments in nitrogen and different characterization techniques were used to determine their physical and electrical properties before and after ultraviolet (UV) irradiation. Before high thermal treatment, X-ray diffraction patterns show that the main diffraction peaks for the obtained TiO2:SiO2 films correspond to the crystalline phase of rutile-TiO2. Infrared analyses before and after thermal treatment show significant changes in the chemical bonding of the final films relative to the temperatures used during annealing. Also, UV–visible spectra provide a constant optical band gap for the films, independent of different TiO2 concentrations as expected. On the other hand, atomic-force microscopy measurements before and after UV irradiation show an appreciable difference in the grain size and surface morphology of the resulting TiO2:SiO2 oxides annealed at 1000 °C. Finally, photoelectrical I–V properties were obtained for all TiO2:SiO2 films by depositing ultrathin titanium stripes on top of the photoactive material and then, measuring the total current flowing through the metal electrode before and after UV irradiation. From these last measurements, a detectable increase in the I–V slope (lower resistance of the titanium stripe) is found for all samples during UV exposure, thus making this device to act as a simple photoresistor based on r-TiO2 particles.

Stable anatase TiO2 formed by calcination of rice-like titania nanorod at 800 °C exhibits high photocatalytic activity

RSC Advances ◽  
2014 ◽  
Vol 4 (47) ◽  
pp. 24704-24709 ◽  
Author(s):  
Inderpreet Singh Grover ◽  
Satnam Singh ◽  
Bonamali Pal
Keyword(s):  
Photocatalytic Activity ◽  
High Temperature ◽  
Thermal Treatment ◽  
Crystalline Phase ◽  
Rutile Phase ◽  
High Photocatalytic Activity ◽  
Anatase Tio2

This paper demonstrates the complete retention (>98%) of anatase TiO2 crystalline phase after high temperature (800 °C) thermal treatment of rice-like TiO2 nanorods (length = 81–134 nm, diameter = 8–13 nm) relative to 100% conversion of the rutile phase after calcination of P25-TiO2 under similar conditions.

THE TRANSITION FROM AMORPHOUS SILICON OXIDE TO CRYSTALLINE SILICON STUDIED BY PHOTOELECTRON DIFFRACTION

2002 ◽  
Vol 09 (02) ◽  
pp. 735-740 ◽  
Author(s):  
C. WESTPHAL ◽  
S. DREINER ◽  
M. SCHÜRMANN ◽  
H. ZACHARIAS
Keyword(s):  
Least Squares ◽  
Amorphous Silicon ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Sharp Interface ◽  
Oxidation States ◽  
Photoelectron Diffraction ◽  
Least Squares Fitting ◽  
Amorphous Silicon Oxide ◽  
Diffraction Patterns

Angle-scanned photoelectron diffraction patterns of the Si 2p signal of oxidized Si(111) and Si(001) surfaces have been recorded and compared with simulations. The chemically shifted components of the Si 2p signal were deconvoluted by least squares fitting. The different oxidation states exhibit individual diffraction patterns for both surface orientations, indicating a different environment for each suboxide. For the Si(111) surface the results agree with a previously proposed sharp interface, whereas a graded interface is indicated for the Si(001) surface.

scholarly journals Electrical Characterization of Sol-Gel Derived TiO2Film on c-Si Substrate by Admittance Measurement

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Ayşe Evrim Saatci ◽  
Orhan Özdemir
Keyword(s):  
Crystalline Silicon ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Metal Electrode ◽  
Dip Coating ◽  
Current Voltage ◽  
Dta Analysis ◽  
Dip Coating Technique ◽  
And Storage

Transport and storage properties of sol-gel synthesized, namely, dip coating technique, titanium dioxide (TiO2) thin film over crystalline silicon (c-Si), has been investigated by means of current-voltage (I-V) and admittance analysis within different ambient. Considering the work function of anatase TiO2film, determined by both FTIR and TG/DTA analysis, silver (Ag) as front metal electrode was chosen to hinder a barrier for charge carriers. Electrical analysis implied that Ag/TiO2/c-Si structure was actually constituted by Ag/TiO2/native silicon dioxide (SiO2)/c-Si [SIS] structure, in which SiO2layer was identified by FTIR analysis. Consequently, the electrical features of the film were interpreted in terms of SIS diode that is capable of explaining C-V features.

scholarly journals Influence of thermal treatment on color change of beech wood with red heartwood

2016 ◽  
pp. 239-256
Author(s):  
Nebojsa Todorovic ◽  
Zdravko Popovic ◽  
Goran Milic ◽  
Ranko Popadic
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Cross Section ◽  
Color Change ◽  
Beech Wood ◽  
Color Difference ◽  
Mean Values ◽  
Before And After ◽  
Section Surface ◽  
The Difference

The goal of this word was to examine the parameters of color of beech wood before and after thermal treatment, and to determine if there is a difference in color between sapwood and red heartwood before and after application of high temperature. Samples were treated at temperatures of 170?C, 190?C and 210?C, respectively, during 4 hours. Color coordinates (CIEL*a*b* system) were measured before and after treatment by using the following parameters: ?L, ?a, ?b and ?E - color change. Color was assessed at four spots on the radial and cross-section surfaces of wood and their mean values were taken for further calculations. Acquired results show that the applied heat treatment of sapwood did not significantly influence the change of color difference between cross-section and radial surfaces. The difference between cross-section and radial surfaces, in nontreated red heartwood was smaller than that measured in sapwood. The color difference of nontreated sapwood and red heartwood was more pronounced on the radial than on the cross-section surface. Application of high temperature caused a significant decrease of this difference. Temperature of 210?C caused the smallest color difference between these two parts of wood which was in this research determined on the radial surface. It was concluded that the applied thermal treatment almost equalized the colors of sapwood and red heartwood, especially on the radial surface, and from this aspect it can be concluded that these two parts of beech wood were completely equalized. It should also be noted that in the case of equalized properties, sapwood and red heartwood can be equally applied in a final product made of thermally treated beech wood.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Mechanoactivation Of Rice Husk Ash In Laboratory Conditions

2019 ◽  
pp. 20-26
Keyword(s):  
Mechanical Activation ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Silicon Oxide ◽  
Rice Husk Ash ◽  
Pozzolanic Activity ◽  
Maximum Solubility ◽  
Laboratory Conditions ◽  
Before And After ◽  
Mineral Additive

In many rice producing countries of the world, including in Vietnam, various research aimed at using rice husk ash (RHA) as a finely dispersed active mineral additive in cements, concrete and mortars are being conducted. The effect of the duration of the mechanoactivation of the RHA, produced under laboratory conditions in Vietnam, on its pozzolanic activity were investigated in this study. The composition of ash was investigated by laser granulometry and the values of indicators characterizing the dispersion of its particles before and after mechanical activation were established. The content of soluble amorphous silicon oxide in rice husk ash samples was determined by photocolorimetric analysis. The pizzolanic activity of the RHA, fly ash and the silica fume was also compared according to the method of absorption of the solution of the active mineral additive. It is established that the duration of the mechanical activation of rice husk ash by grinding in a vibratory mill is optimal for increasing its pozzolanic activity, since it simultaneously results in the production of the most dispersed ash particles with the highest specific surface area and maximum solubility of the amorphous silica contained in it. Longer grinding does not lead to further reduction in the size of ash particles, which can be explained by their aggregation, and also reduces the solubility of amorphous silica in an aqueous alkaline medium.

ENDURO 19-9SMo

Alloy Digest ◽  
1968 ◽  
Vol 17 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Thermal Treatment ◽  
Physical Properties ◽  
Surface Treatment ◽  
Heat Treating ◽  
Temperature Performance ◽  
Type Stainless Steel

Abstract ENDURO 19-9-SMo is a 19-9 type stainless steel containing molybdenum to greatly increase its resistance to attack by most chemicals. It is nonmagnetic and does not respond to thermal treatment for hardening. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-207. Producer or source: Republic Steel Corporation.

Integrated ESD Robustness through Device Analysis of Ultra-Small Low Voltage Power MOSFETs

2014 ◽  
Author(s):  
Ian Kearney ◽  
Hank Sung
Keyword(s):  
New Product Development ◽  
Silicon Oxide ◽  
Low Voltage ◽  
Photon Emission ◽  
Electrical Characterization ◽  
Power Mosfets ◽  
Low Leakage ◽  
A Cell ◽  
Thermographic Analysis ◽  
Voltage Spike

Abstract Low voltage power MOSFETs often integrate voltage spike protection and gate oxide ESD protection. The basic concept of complete-static protection for the power MOSFETs is the prevention of static build-up where possible and the quick, reliable removal of existing charges. The power MOSFET gate is equivalent to a low voltage low leakage capacitor. The capacitor plates are formed primarily by the silicon gate and source metallization. The capacitor dielectric is the silicon oxide gate insulation. Smaller devices have less capacitance and require less charge per volt and are therefore more susceptible to ESD than larger MOSFETs. A FemtoFETTM is an ultra-small, low on-resistance MOSFET transistor for space-constrained handheld applications, such as smartphones and tablets. An ESD event, for example, between a fingertip and the communication-port connectors of a cell phone or tablet may cause permanent system damage. Through electrical characterization and global isolation by active photon emission, the authors identify and distinguish ESD failures. Thermographic analysis provided additional insight enabling further separation of ESD failmodes. This paper emphasizes the role of failure analysis in new product development from the create phase through to product ramp. Coupled with device electrical simulation, the analysis observations led to further design enhancement.

Analysis of an Anomalous CMOS Transistor Exhibiting Drain to Source Leakage—Its Model and Cause

2014 ◽  
Author(s):  
Yuk L. Tsang ◽  
Alex VanVianen ◽  
Xiang D. Wang ◽  
N. David Theodore
Keyword(s):  
Threshold Voltage ◽  
Crystalline Silicon ◽  
Electrical Characterization ◽  
Visual Defect ◽  
Scanning Capacitance Microscopy ◽  
Device Model ◽  
Graphical Simulation ◽  
Cmos Transistor

Abstract In this paper, we report a device model that has successfully described the characteristics of an anomalous CMOS NFET and led to the identification of a non-visual defect. The model was based on detailed electrical characterization of a transistor exhibiting a threshold voltage (Vt) of about 120mv lower than normal and also exhibiting source to drain leakage. Using a simple graphical simulation, we predicted that the anomalous device was a transistor in parallel with a resistor. It was proposed that the resistor was due to a counter doping defect. This was confirmed using Scanning Capacitance Microscopy (SCM). The dopant defect was shown by TEM imaging to be caused by a crystalline silicon dislocation.

scholarly journals Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1803
Author(s):  
Zhen Zheng ◽  
Junyang An ◽  
Ruiling Gong ◽  
Yuheng Zeng ◽  
Jichun Ye ◽  
...  
Keyword(s):  
Structural Changes ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Contact Potential Difference ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Carrier Lifetimes ◽  
Transmission Electron ◽  
Effective Carrier

In this work, we report the same trends for the contact potential difference measured by Kelvin probe force microscopy and the effective carrier lifetime on crystalline silicon (c-Si) wafers passivated by AlOx layers of different thicknesses and submitted to annealing under various conditions. The changes in contact potential difference values and in the effective carrier lifetimes of the wafers are discussed in view of structural changes of the c-Si/SiO2/AlOx interface thanks to high resolution transmission electron microscopy. Indeed, we observed the presence of a crystalline silicon oxide interfacial layer in as-deposited (200 °C) AlOx, and a phase transformation from crystalline to amorphous silicon oxide when they were annealed in vacuum at 300 °C.

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