Nitrogen-Doping Induced Optical Bandgap Widening of P-Type Cu2O Flms

AbstractWe have investigated the effect of N doping into Cu2O films deposited by reactive magnetron sputtering. With increasing N-doping concentration up to 3 at.%, the optical bandgap energy is enlarged from ˜2.1 to ˜2.5 eV with retaining p-type conductivity as determined by optical absorption and Hall-effect measurements. Additionally, photoelectron spectroscopy in air measurements shows an increase in the valence and conduction band shifts with N doping. These experimental results demonstrate possible optical bandgap widening of p-type N-doped Cu2O films, which is a phenomenon that is probably associated with significant structural changes induced by N doping, as suggested from x-ray diffraction measurements.

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Properties of Sputter Deposited ZnO Films Co-doped with Lithium and Phosphorus

MRS Proceedings ◽

10.1557/opl.2013.4 ◽

2013 ◽

Vol 1494 ◽

pp. 77-82

Author(s):

T. N. Oder ◽

A. Smith ◽

M. Freeman ◽

M. McMaster ◽

B. Cai ◽

...

Keyword(s):

Rf Magnetron Sputtering ◽

Zno Films ◽

X Ray Diffraction ◽

X Ray ◽

Sapphire Substrates ◽

Hall Effect Measurements ◽

Sputter Deposited ◽

P Type ◽

Post Deposition ◽

Co Doped

ABSTRACTThin films of ZnO co-doped with lithium and phosphorus were deposited on sapphire substrates by RF magnetron sputtering. The films were sequentially deposited from ultra pure ZnO and Li3PO4 solid targets. Post deposition annealing was carried using a rapid thermal processor in O2 and N2 at temperatures ranging from 500 °C to 1000 °C for 3 min. Analyses performed using low temperature photoluminescence spectroscopy measurements reveal luminescence peaks at 3.359, 3.306, 3.245 eV for the co-doped samples. The x-ray diffraction 2θ-scans for all the films showed a single peak at about 34.4° with full width at half maximum of about 0.17°. Hall Effect measurements revealed conductivities that change from p-type to n-type over time.

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FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

Materials Express ◽

10.1166/mex.2021.1957 ◽

2021 ◽

Vol 11 (5) ◽

pp. 706-716

Author(s):

Nada D. Al-Khthami ◽

Tariq Altalhi ◽

Mohammed Alsawat ◽

Mohamed S. Amin ◽

Yousef G. Alghamdi ◽

...

Keyword(s):

Visible Light ◽

Photoelectron Spectroscopy ◽

Sol Gel ◽

Bandgap Energy ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Reduced Graphene ◽

Structural Surface ◽

Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

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Copper Containing Glass-Based Bone Adhesives for Orthopaedic Applications: Glass Characterization and Advanced Mechanical Evaluation

10.1101/2020.11.19.390138 ◽

2020 ◽

Author(s):

Sahar. Mokhtari ◽

Anthony.W. Wren

Keyword(s):

Mechanical Properties ◽

Photoelectron Spectroscopy ◽

Structural Changes ◽

Viscoelastic Behavior ◽

Polymer Chains ◽

Nano Particles ◽

X Ray Diffraction ◽

X Ray ◽

Compression Data

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.

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Gold nanoclusters reductively deposited on porous silicon: morphology and electronic structures

Canadian Journal of Chemistry ◽

10.1139/v98-146 ◽

1998 ◽

Vol 76 (11) ◽

pp. 1707-1716 ◽

Cited By ~ 30

Author(s):

I Coulthard ◽

S Degen ◽

Y -J Zhu ◽

T K Sham

Keyword(s):

Gold Nanoparticles ◽

Porous Silicon ◽

Photoelectron Spectroscopy ◽

Gold Nanoclusters ◽

Gold Complex ◽

X Ray Diffraction ◽

Complex Ions ◽

X Ray ◽

Preparation Conditions ◽

P Type

Utilizing porous silicon as a reducing agent and a substrate, gold complex ions [AuCl4]- were reduced from aqueous solution to produce nanoparticles of gold upon the surface of porous silicon. Scanning electron microscopy (SEM) was utilized to study the morphology of the porous silicon layers and the deposits of gold nanoparticles. It is found that preparation conditions have a profound effect on the morphology of the deposits, especially on porous silicon prepared from a p-type wafer. The gold nanoparticles, varying from micrometric aggregates of clusters of the order of 10 nm, to a distribution of nearly spherical clusters of the order of 10 nm, to strings of ~10 nm were observed and compared to bulk gold metal using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). These techniques confirm and complement the SEM findings. The potential for this reductive deposition technique is noted.Key words: gold nanostructures, reductive deposition, porous silicon, morphology, X-ray spectroscopy.

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An X-ray Diffraction Investigation of Tin Oxide Deposition and Annealing

MRS Proceedings ◽

10.1557/proc-666-f1.7 ◽

2001 ◽

Vol 666 ◽

Cited By ~ 2

Author(s):

Joshua J. Robbins ◽

Yen-Jung Huang ◽

Mailasu Bai ◽

Tyrone Vincent ◽

Colin A. Wolden

Keyword(s):

Electrical Properties ◽

Tin Oxide ◽

Structural Changes ◽

Chemical Vapor ◽

Transparent Conductor ◽

X Ray Diffraction ◽

X Ray ◽

Oxide Deposition ◽

Hall Effect Measurements ◽

Bombardment Energy

ABSTRACTTin oxide thin films were deposited by plasma-enhanced chemical vapor deposition (PECVD) for applications as a transparent conductor. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to quantify the crystal structure and morphology of these films both as-deposited and after annealing conditions. Annealing was performed in an argon environment as a function of time and temperature. Although annealing was found to significantly improve electrical properties, the structure as measured by XRD remained largely unchanged. Hall effect measurements show that the improvements in resistivity are due to increases in carrier concentration. XRD did reveal that films deposited on the powered electrode had a film orientation that was distinctly different than films deposited on the grounded electrode. These changes suggest the importance of ion bombardment energy. The structural changes were correlated with improved electrical properties.

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Photoelectrochemical properties of N-doped self-organized titania nanotube layers with different thicknesses

Journal of Materials Research ◽

10.1557/jmr.2006.0344 ◽

2006 ◽

Vol 21 (11) ◽

pp. 2824-2828 ◽

Cited By ~ 75

Author(s):

J.M. Macak ◽

A. Ghicov ◽

R. Hahn ◽

H. Tsuchiya ◽

P. Schmuki

Keyword(s):

Photoelectron Spectroscopy ◽

Nitrogen Doping ◽

Electrochemical Anodization ◽

Tube Length ◽

Ammonia Treatment ◽

X Ray Diffraction ◽

X Ray ◽

Self Organized ◽

Structure Morphology ◽

N Doping

The present work reports nitrogen doping of self-organized TiO2 nanotubular layers. Different thicknesses of the nanotubular layer architecture were formed by electrochemical anodization of Ti in different fluoride-containing electrolytes; tube lengths were 500 nm, 2.5 μm, and 6.1 μm. As-formed nanotube layers were annealed to an anatase structure and treated in ammonia environment at 550 °C to achieve nitrogen doping. The crystal structure, morphology, composition and photoresponse of the N-doped were characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and photoelectrochemical measurements. Results clearly show that successful N-doping of the TiO2 nanotubular layers can be achieved upon ammonia treatment. The magnitude of the photoresponse in ultraviolet and visible light is strongly dependent on the thicknesses of the layers. This effect is ascribed to recombination effects along the tube length.

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Characterization of p-type 4H-SiC epitaxial layer grown on (11-20) substrate

MRS Proceedings ◽

10.1557/proc-680-e9.2 ◽

2001 ◽

Vol 680 ◽

Cited By ~ 1

Author(s):

Kazutoishi Kojima ◽

Toshiyuki Ohno ◽

Mituhiro Kushibe ◽

Koh Masahara ◽

Yuuki Ishida ◽

...

Keyword(s):

Boron Concentration ◽

Hole Mobility ◽

Crystalline Quality ◽

Diffraction Measurement ◽

X Ray Diffraction ◽

X Ray ◽

Hall Effect Measurements ◽

P Type ◽

Incorporation Efficiency

ABSTRACTGrowth and characterization of p-type 4H-SiC epitaxial layers grown on (11-20) substrates are reported. P-type 4H-SiC epilayers with smooth surface morphology have been grown on (11-20) substrates by low-pressure, hot-wall type CVD with SiH4–C3H8–H2–TMA system. The doping concentration can be controlled in the range from about 1×1016cm−3 to 1×1019cm−3. Anisotropy of the crystalline quality is observed by x-ray diffraction measurement. P-type epilayers, in which near band-gap emissions are dominated and D-A pair peak is not observed, are obtained. Hole mobility of (11-20) epilayers is smaller than that of (0001) epilayers probably due to the lack of crystalline quality compared to (0001) epilayers. The results of both low-temperature photoluminescence and the temperature dependence of Hall effect measurements indicate that the boron concentration as undoped impurity in (11-20) epilayer is lower than that of (0001) epilayer. This may be caused by the smaller incorporation efficiency of boron into (11-20) epilayer than that of (0001) epilayer.

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Characteristics of Porous 3C-SiC Thin Films Formed with Nitrogen Doping Concentrations

Materials Science Forum ◽

10.4028/www.scientific.net/msf.645-648.391 ◽

2010 ◽

Vol 645-648 ◽

pp. 391-394

Author(s):

Kang San Kim ◽

Gwiy Sang Chung

Keyword(s):

Thin Films ◽

Photo Luminescence ◽

X Ray Diffraction ◽

Average Pore ◽

X Ray ◽

Uv Led ◽

N Doping ◽

P Type ◽

Sic Films

This paper describes the characteristics of porous 3C-SiC with in-situ N-doping concentrations. Polycrystalline (poly) 3C-SiC thin films were deposited on p-type Si (100) substrates by APCVD using hexamethyildisilane (HMDS: Si2(CH3)6). The porous 3C-SiC (pSiC) was achieved by anodized with 380 nm UV-LED. The characteristics of the N2 doped pSiC were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and photo luminescence (PL). Average pore diameter is about 50 nm and etched area was increased with N2 doping rate. These results are attributed to decrease the crystallinity by N2 doping. The band gaps of poly 3C-SiC films and porous 3C-SiC films were 2.5 eV and 2.7 eV, respectively.

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Dopant and As4/Ga Flux Ratio Influence on the Electrical and Structural Properties of LT GaAs

MRS Proceedings ◽

10.1557/proc-340-295 ◽

1994 ◽

Vol 340 ◽

Cited By ~ 1

Author(s):

S. P. O'Hagan ◽

M. Missous

Keyword(s):

Substrate Temperature ◽

Pressure Ratio ◽

Flux Ratio ◽

X Ray Diffraction ◽

Double Crystal ◽

Strong Function ◽

X Ray ◽

Undoped Material ◽

Hall Effect Measurements ◽

P Type

ABSTRACTDouble crystal x-ray diffraction and Hall effect measurements have been performed on GaAs layers grown by molecular beam epitaxy at low substrate temperature (200-250°C). The concentration of excess As incorporated in undoped material is found to be a strong function of growth temperature but not of As4/Ga beam equivalent pressure ratio at a given temperature. Doping with Si or Be at concentrations of 1019cm−3 or greater has resulted in significant reduction of excess As concentration in layers grown at 250'C. This effect is seen to diminish with reducing substrate temperature. The effect is not seen when Se is used as the doping source. Reducing As overpressure in the presence of such a high doping concentrations has led to highly electrically active n- and p-type layers grown at 250'C.

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Synthesis of ZnAl2O4 and Evaluation of the Response in Propane Atmospheres of Pellets and Thick Films Manufactured with Powders of the Oxide

Sensors ◽

10.3390/s21072362 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2362

Author(s):

Emilio Huízar-Padilla ◽

Héctor Guillén-Bonilla ◽

Alex Guillén-Bonilla ◽

Verónica-María Rodríguez-Betancourtt ◽

A. Sánchez-Martínez ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Electrical Conductance ◽

Bandgap Energy ◽

X Ray Diffraction ◽

Static Test ◽

X Ray ◽

Electron Microscopies ◽

Oxide Powders ◽

Vis Spectroscopy ◽

Colloidal Method

ZnAl2O4 nanoparticles were synthesized employing a colloidal method. The oxide powders were obtained at 300 °C, and their crystalline phase was corroborated by X-ray diffraction. The composition and chemical structure of the ZnAl2O4 was carried out by X-ray and photoelectron spectroscopy (XPS). The optical properties were studied by UV-vis spectroscopy, confirming that the ZnAl2O4 nanoparticles had a direct transition with bandgap energy of 3.2 eV. The oxide’s microstructures were microbars of ~18.2 nm in size (on average), as analyzed by scanning (SEM) and transmission (TEM) electron microscopies. Dynamic and stationary gas detection tests were performed in controlled propane atmospheres, obtaining variations concerning the concentration of the test gas and the operating temperature. The optimum temperatures for detecting propane concentrations were 200 and 300 °C. In the static test results, the ZnAl2O4 showed increases in propane response since changes in the material’s electrical conductance were recorded (conductance = 1/electrical resistance, Ω). The increases were ~2.8 at 200 °C and ~7.8 at 300 °C. The yield shown by the ZnAl2O4 nanoparticles for detecting propane concentrations was optimal compared to other similar oxides categorized as potential gas sensors.

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