scholarly journals EFFECT OF SUNLIGHT ON THE ELECTRICAL CHARACTERISTICS OF THE HETEROSTRUCTURE TITANIUM DIOXIDE/SILICON

Doklady BGUIR ◽  
2019 ◽  
pp. 136-143
Author(s):  
A. A. Kuraptsova ◽  
A. L. Danilyuk ◽  
A. A. Leshok ◽  
V. E. Borisenko
Keyword(s):  
Titanium Dioxide ◽  
Wide Band ◽  
Charge Carriers ◽  
Electrical Characteristics ◽  
Wide Band Gap ◽  
External Bias ◽  
Modeling Process ◽  
Semiconducting Metal Oxides ◽  
The Difference ◽  
Sun Light

Electrical characteristics of the heterostructure titanium dioxide/silicon illuminated by the sun light were theoretically modeled. The modeling process includes consideration of generation of the charge carriers and their transport through the practically important heterostructure n-TiO2/p-Si. The current through the structure under small external bias up to 0.6 V was found to depend nonlinearly on the light wavelength. It is controlled by the movement of the electrons from silicon to the titanium dioxide. The highest current corresponds to the wavelengths of about 600 nm. The results obtained are explained by the difference in the absorption coefficients and reflectivity of titanium dioxide and silicon which determine generation of nonequilibrium charge carriers in the heterostructure n-TiO2/p-Si. It was demonstrated that under illumination of the unbiased heterostructure with the light of 500–600 nm the generated electrons freely move from the titanium dioxide to silicon while the movement of holes is blocked. It helps to concentrate electrons in the relatively thin nearsurface layer of titanium dioxide and use them for catalytic purification of water and air by oxidation of organic pollutants at its surface. The regularities observed are important in the detailed analysis of electronic processes at the surface of wide band gap semiconducting metal oxides and their practical application in photocatalytic processes.

scholarly journals Titanium Dioxide Nanotube-Based Oxygen Indicator for Modified Atmosphere Packaging: Efficiency and Accuracy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2410 ◽  
Author(s):  
Junwei Wen ◽  
Shuting Huang ◽  
Yu Sun ◽  
Zhengjie Chen ◽  
Yixiang Wang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Modified Atmosphere Packaging ◽  
Wide Band ◽  
Crystal Form ◽  
Tio2 Nanotube ◽  
Hydroxyethyl Cellulose ◽  
Modified Atmosphere ◽  
Destructive Testing ◽  
Wide Band Gap ◽  
Pet Film

Colorimetric oxygen indicators can be applied for non-destructive testing in packaging; especially in modified atmosphere packaging (MAP). In this paper; titanium dioxide (TiO2) nanotube; which is used as a semiconductor photocatalyst in oxygen indicators; was synthesized via a microwave-assisted hydrothermal method. X-Ray Diffraction (XRD) was used to analyze its crystal form and Scanning Electron Microscope (SEM).to characterize its morphology. Its properties were studied using Brunauer-Emmett-Teller (BET), Diffuse Reflection Spectrum (DRS), and Bluebottle experiments. The results showed that the synthesized TiO2 nanotube was a mixture of rutile and anatase; with a specific surface area of 190.35 m2/g; and a wide band gap of 3.34 eV. Given the satisfactory performance; the TiO2-based oxygen indicator was prepared and combined with glycerol; methylene blue; and hydroxyethyl cellulose (HEC). The oxygen indicator demonstrated excellent photocatalytic performance and effectively avoided excitation by visible light. We studied the rheological properties; thixotropic properties; and wettability of the indicator. The results demonstrated the printability of the indicator solution; which was then printed in the polyethylene terephthalate (PET) film by screen printing and applied to MAP. The application results showed that the prepared oxygen indicator was able to provide visual support to judge whether the packaging was intact and the food was safe.

scholarly journals AX2: Type of compounds and an overview of theoretically investigated TiO2

2020 ◽  
Vol 9 (2) ◽  
pp. 79-87
Author(s):  
Dušica Jovanović ◽  
Jelena Zagorac ◽  
Branko Matović ◽  
Aleksandra Zarubica
Keyword(s):  
Band Gap ◽  
Wide Band ◽  
Theoretical Studies ◽  
Chemical Bonds ◽  
Wide Band Gap ◽  
Specific Temperature ◽  
Temperature And Pressure ◽  
The Difference ◽  
The Stability ◽  
Experimental And Theoretical Studies

AX 2-type compounds can be ionic, covalent or molecular types of structure, which depends on the size of atoms and the polarization properties. The materials of such type of the structure have different properties that can find the application in various areas of science and industry. Titanium dioxide, as a material of AX 2-type of the structure is a wide band gap semiconductor that has been widely investigated due to its photocatalytic properties and applicability for various purposes, such as the production of solar cells, decontamination of pollutants, elimination of microorganisms, suppression of cancer cells, etc. Experimental and theoretical studies of this metal oxide can give different data on the stability of individual crystalline modifications and their transitions. This study has presented an overview of theoretically examined TiO 2 modifications and current problems that can be encountered (such as various band gap values obtained by different methods and functionals; the difference between the stability of modifications examined on ab initio level and experimentally; the character of chemical bonds and transitions at the specific temperature and pressure conditions…) and overrun by optimal corrections added in calculations.

ON PRODUCTION POSSIBILITY TITANIUM DIOXIDE POWDER SYNTHESIZED BY DYNAMIC PLAZMA METHOD

2020 ◽  
Vol 11 ◽  
pp. 21-26
Author(s):  
A. A. SIVKOV ◽  
◽  
YU. N. VYMPINA ◽  
A. S. IVASHUTENKO ◽  
I. A. RAKHMATULLIN ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Alternative Energy ◽  
Wide Band ◽  
Coarse Fraction ◽  
Wide Band Gap ◽  
Plasma Dynamic ◽  
Dynamic Synthesis ◽  
Titanium Dioxide Powder ◽  
Dioxide Powder ◽  
Photocatalytic Material

These days, environmental pollution problems are relevant, therefore, the problems associated with photocatalysis as a direction for the future development of alternative energy are solved by many world scientists. Titanium dioxide TiO2 is known to be a photocatalytic material with many unique properties. However, its use is limited due to its wide band gap and the high recombination rate of electron pairs. The method of direct plasma dynamic synthesis of dispersed titanium dioxide was proposed. It was established that the synthesized product consisted of two fractions which had different sizes: a coarse fraction with particle sizes from ~10 microns to ~100 microns and a fine one - from ~10 nm to ~1 micron. It was also revealed that fractions mainly consisted of two TiO2 crystalline modifications: anatase and rutile with tetragonal syngony.

Secondary Electron Potential Contrast for Dopant Profiling of Silicon Carbide Devices

2006 ◽  
Author(s):  
Marco Buzzo ◽  
Mauro Ciappa ◽  
Wolfgang Fichtner
Keyword(s):  
Silicon Carbide ◽  
Wide Band ◽  
Wide Band Gap ◽  
Experimental Conditions ◽  
Dopant Profiling ◽  
Wide Band Gap Semiconductors ◽  
The Difference ◽  
Main Component ◽  
The Impact ◽  
Relevant Factors

Abstract Secondary electrons potential contrast (SEPC) by scanning electron microscopy has emerged as a powerful tool for two-dimensional quantitative dopant imaging. The main component of the SEPC signal arises from the difference in the built-in potential between differently doped regions; which is very high in wide-band-gap semiconductors and particularly intense in SiC. This paper, after discussing the physical principles leading to the dopant contrast and the proper experimental setup, investigates the impact of relevant factors such as experimental conditions, surface effects, and sample preparation on image quality. The quantitative capabilities of this technique are demonstrated by the analysis of different test structures and prototypes of power devices such as MOSFET and JFET. The application to completely process devices demonstrates that SEPC represents an unequalled characterization technique, which provides accurate imaging and dopant profiling capabilities for silicon carbide devices.

Visible and Deep Ultraviolet Study of SiC/SiO2 Interface

2012 ◽  
Vol 711 ◽  
pp. 118-123
Author(s):  
Pawel Borowicz ◽  
Tomasz Gutt ◽  
Tomasz Malachowski ◽  
Mariusz Latek
Keyword(s):  
Oxidation Process ◽  
Electronic Devices ◽  
Wide Band ◽  
Charge Carriers ◽  
Wide Band Gap ◽  
Surface Mobility ◽  
Mobility Of Charge Carriers ◽  
Deep Ultraviolet ◽  
The Subject ◽  
Non Destructive

Silicon carbide (SiC) is a wide band gap semiconductor having good thermal conductivity and high break down voltage. Formation of SiO2layer in thermal oxidation process completes the set of properties of SiC as a promising material for fabrication of high power and high frequency electronic devices. This picture is perturbed by Near Interface Traps (NIT's) that decrease the surface mobility of charge carriers. The origin of NIT's is still the subject of discussion and there are several candidates for NIT's. One possibility is the formation of carbonic structures during the process of manufacturing of MOS-type structures. The aim of this work was to look for possible carbonic inclusions with Raman spectroscopy. The attention of authors was focused on non-destructive way of application of the experimental technique.

scholarly journals Broad-Spectrum Antimicrobial Effects of Photocatalysis Using Titanium Dioxide Nanoparticles Are Strongly Potentiated by Addition of Potassium Iodide

2016 ◽  
Vol 60 (9) ◽  
pp. 5445-5453 ◽  
Author(s):  
Ying-Ying Huang ◽  
Hwanjun Choi ◽  
Yu Kushida ◽  
Brijesh Bhayana ◽  
Yuguang Wang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Potassium Iodide ◽  
Environmental Remediation ◽  
Titanium Dioxide Nanoparticles ◽  
Wide Band ◽  
Dependent Manner ◽  
Wide Band Gap ◽  
Content Type ◽  
Uva Light ◽  
Bacteria And Fungi

ABSTRACTPhotocatalysis describes the excitation of titanium dioxide nanoparticles (a wide-band gap semiconductor) by UVA light to produce reactive oxygen species (ROS) that can destroy many organic molecules. This photocatalysis process is used for environmental remediation, while antimicrobial photocatalysis can kill many classes of microorganisms and can be used to sterilize water and surfaces and possibly to treat infections. Here we show that addition of the nontoxic inorganic salt potassium iodide to TiO2(P25) excited by UVA potentiated the killing of Gram-positive bacteria, Gram-negative bacteria, and fungi by up to 6 logs. The microbial killing depended on the concentration of TiO2, the fluence of UVA light, and the concentration of KI (the best effect was at 100 mM). There was formation of long-lived antimicrobial species (probably hypoiodite and iodine) in the reaction mixture (detected by adding bacteria after light), but short-lived antibacterial reactive species (bacteria present during light) produced more killing. Fluorescent probes for ROS (hydroxyl radical and singlet oxygen) were quenched by iodide. Tri-iodide (which has a peak at 350 nm and a blue product with starch) was produced by TiO2-UVA-KI but was much reduced when methicillin-resistantStaphylococcus aureus(MRSA) cells were also present. The model tyrosine substrateN-acetyl tyrosine ethyl ester was iodinated in a light dose-dependent manner. We conclude that UVA-excited TiO2in the presence of iodide produces reactive iodine intermediates during illumination that kill microbial cells and long-lived oxidized iodine products that kill after light has ended.

Plasmonic Photosensitization of a Wide Band Gap Semiconductor: Converting Plasmons to Charge Carriers

Nano Letters ◽  
2011 ◽  
Vol 11 (12) ◽  
pp. 5548-5552 ◽  
Author(s):  
Syed Mubeen ◽  
Gerardo Hernandez-Sosa ◽  
Daniel Moses ◽  
Joun Lee ◽  
Martin Moskovits
Keyword(s):  
Band Gap ◽  
Wide Band ◽  
Charge Carriers ◽  
Wide Band Gap

scholarly journals Photocatalytic Applications of Titanium Dioxide (TiO2)

2021 ◽  
Author(s):  
Atta ul Haq ◽  
Muhammad Saeed ◽  
Samreen Gul Khan ◽  
Muhammad Ibrahim
Keyword(s):  
Water Pollution ◽  
Titanium Dioxide ◽  
Metal Oxides ◽  
Textile Industry ◽  
Photocatalytic Performance ◽  
Wide Band ◽  
Catalytic Performance ◽  
Wide Band Gap ◽  
Rapid Industrialization ◽  
Photocatalytic Applications

Water pollution is one the fundamental problems that have got the serious concerns of the researchers. Water poluution arises due to a number of reasons including domestic, industrial, agricultural, scinec and technology. The textile industry is the main industry that releases the dyes contaminated wastewater to the environment. A varities of protocols have been attempeted for the removal of dyes from aqueous body. Photocatalysis is one of the effective techniques which offer opportunities to overcome the aqueous pollution caused by rapid industrialization and urbanization. The semiconductor metal oxides used as photocatalysts are capable to provide a sustainable and clean ecosystem due to the tunable physiochemical characteristics of semiconductor metal oxides. Titanium dioxide (TiO2) is one of the metal oxides that can be effectively employed as a photocatalyst in the abatement of aqueous pollution due to organic compounds. The catalytic performance of titanium dioxide depends on several parameters like its crystallinity, surface area, and morphology. Titanium dioxide has shown good performance in the different photocatalytic systems, however, the characteristics like wide band gap and low conductivity limit the photocatalytic performance of titanium dioxide. Various attempts have been made to improve the photocatalytic performance of titanium dioxide. Herein, we summarize the various attempts to improve the photocatalytic performance of titanium dioxide in the abatement of aqueous pollution. The attempts made for the improvement of photocatalytic performance of titanium dioxide include modifications in composition, doping of other metal, and formation of heterojunctions with other metal oxides.

scholarly journals BiOCOOH Microflowers Decorated with Ag/Ag2CrO4 Nanoparticles as Highly Efficient Photocatalyst for the Treatment of Toxic Wastewater

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 93 ◽  
Author(s):  
Shijie Li ◽  
Bing Xue ◽  
Jialin Chen ◽  
Wei Jiang ◽  
Yanping Liu
Keyword(s):  
Photocatalytic Performance ◽  
Wide Band ◽  
Active Species ◽  
Charge Carriers ◽  
The Novel ◽  
Wide Band Gap ◽  
Morphological Studies ◽  
Wide Band Gap Semiconductors ◽  
Suppressed Recombination

A novel flower-like Ag/Ag2CrO4/BiOCOOH heterojunction photocatalyst was synthesized by a facile in-situ precipitation strategy combined with photoreduction treatment. Morphological studies revealed that numerous Ag/Ag2CrO4 nanoparticles were evenly anchored on BiOCOOH microflowers, producing a novel heterojunction with the compactly interfacial contact. Optical absorption characterization demonstrated that Ag/Ag2CrO4/BiOCOOH possessed much better sunlight harvesting ability than Ag2CrO4/BiOCOOH and BiOCOOH. Photocatalytic experiments verified that compared with BiOCOOH, Ag2CrO4, Ag/Ag2CrO4, and Ag2CrO4/BiOCOOH, Ag/Ag2CrO4/BiOCOOH achieved remarkable efficiency by eliminating 100% of rhodamine B (RhB), 82.6% of methyl orange (MO) or 69.4% of ciprofloxacin (CIP) within 50 min at a catalyst dosage of 0.4 g/L. The high photocatalytic performance is likely owing to the improved sunlight response and the distinctly suppressed recombination of charge carriers arising from the formation of the novel 3D hierarchical heterostructure. The quenching test signified that h+, and •O2− were detected as the prevailing active species in wastewater treatment. This study may provide a viable strategy for enhancing the photocatalytic performance of wide band-gap semiconductors.

Electrical transport in titania nanoparticles embedded in conducting polymer matrix

2015 ◽  
Vol 4 (5) ◽  
Author(s):  
Ashis Dey
Keyword(s):  
Titanium Dioxide ◽  
Band Gap ◽  
Conducting Polymer ◽  
Polymer Matrix ◽  
Electrical Transport ◽  
Wide Band ◽  
Titania Nanoparticles ◽  
Wide Band Gap ◽  
Semiconductor Nanocomposites

AbstractConducting polymer-wide band gap semiconductor nanocomposites are prepared by polymerizing pyrrole in the presence of colloidal titanium dioxide (TiO

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