Temperature-dependent heterojunction device characteristics of n-ZnO nanorods/p-Si assembly

2020 ◽  
Vol 10 (1) ◽  
pp. 29-36
Author(s):  
Rashad I. Badran ◽  
Yas Al-Hadeethi ◽  
Ahmad Umar ◽  
Saleh H. Al-Heniti ◽  
Bahaaudin M. Raffah ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Hexagonal Phase ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Different Temperatures ◽  
Evaporation Technique ◽  
Wurtzite Hexagonal Phase ◽  
Heterojunction Device ◽  
Increasing Temperature

Heterojunction diode based on n-ZnO nanorods/p-Silicon (Si) assembly was fabricated, examined and reported here. Horizontal quartz tube thermal evaporation technique was used for the growth of ZnO nanorods on Si substrate. The nanorods were characterized by several techniques to examine the structural, morphological, scattering and electrical properties. Wurtzite hexagonal phase of the grown aligned nanorods was observed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The appearance of a sharp Raman peak at 438 cm–1 was observed and it is related to the E2(high) mode of the wurtzite hexagonal phase of ZnO. The electrical properties of the fabricated heterojunction assembly were examined at different temperatures (298∼398 K) in both reverse and forward biased conditions, and a good stability was observed over the entire temperature range. A reduction in the turn-on and breakdown voltage was observed with increasing temperature. By increasing the temperature, the effective potential barrier height was increased, while quality factor was decreased. The observed activation energy was found to be ∼93.4 meV, higher than the exciton binding energy of ZnO.

Hydroquinone Sensor Based on Neodymium (Nd) Doped ZnO Hexagonal Nanorods

2018 ◽  
Vol 10 (3) ◽  
pp. 351-357 ◽  
Author(s):  
Yas Al-Hadeethi ◽  
Ahmad Umar ◽  
Ahmed A. Ibrahim ◽  
Rajesh Kumar ◽  
Saleh. H. Al-Heniti ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Hexagonal Phase ◽  
Zno Nanorods ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Raman Scattering Spectroscopy ◽  
Morphological Studies ◽  
Wurtzite Hexagonal Phase ◽  
Doped Zno ◽  
Hexagonal Nanorods

Herein, we report a simple hydrothermal synthesis and detailed characterizations of Nd-doped ZnO pointed hexagonal nanorods by various techniques such as field emission scanning electron microscopy (FESEM) attached with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-visible, Fourier transform infrared (FTIR) and Raman-scattering spectroscopy. The morphological studies revealed pointed hexagonal nanorods arranged in flower-shaped morphologies and well-crystalline with the wurtzite hexagonal phase. The Nd-doped ZnO nanorods were used as potential scaffold to fabricate high sensitivity hydroquinone sensor which exhibited sensitivity of ∼7.43 μA·mM–1cm–2 with a linear dynamic range of (LDR) of 0.313 mM–2.5 mM and correlation coefficient (R2) of 0.99671. The detection limit of Nd-doped ZnO pointed hexagonal nanorods based hydroquinone sensor was found to be 0.313 mM.

A temperature-dependent structure study of gem-quality hibonite from Myanmar

2010 ◽  
Vol 74 (5) ◽  
pp. 871-885 ◽  
Author(s):  
M. Nagashima ◽  
T. Armbruster ◽  
T. Hainschwang
Keyword(s):  
Room Temperature ◽  
Structure Study ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Trigonal Bipyramidal ◽  
Expansion Coefficients ◽  
Increasing Temperature ◽  
Length Distortion

AbstractThe structure of hibonite from Myanmar (space group P63/mmc, Z = 2, at room temperature a = 5.5909(1), c = 21.9893(4) Å), with simplified formula CaAl12O19 and composition (Ca0.99Na0.01)Σ1.00 was investigated between temperatures of 100 K and 923 K by single-crystal X-ray diffraction methods. Structure refinements have been performed at 100, 296, 473 and 923 K. In hibonite from Myanmar, Ti substitutes for Al mainly at the octahedral Al4 site and, to a lesser degree, at the trigonal bipyramidal site, Al2. The Al4 octahedra build face-sharing dimers. If Ti4+ substitutes at Al4, adjacent cations repulse each other for electrostatic reasons, leading to off-centre cation displacement associated with significant bond-length distortion compared to synthetic (Ti-free) CaAl12O19. Most Mg and smaller proportions of Zn and Si are assigned to the tetrahedral Al3 site. 12-coordinated Ca in hibonite replaces oxygen in a closest-packed layer. However, Ca is actually too small for this site and engages in a ‘rattling-type’ motion with increasing temperature. For this reason, Ca does not significantly increase thermal expansion coefficients of hibonite. The expansion of natural Ti,Mg-rich hibonite between 296 and 923 K along the x and the z axes is αa = 7.64×10–6 K–1 and αc = 11.19×10–6 K–1, respectively, and is thus very similar to isotypic, synthetic CaAl12O19 and LaMgAl11O19 (LMA).

Fabrication and Material Analysis of Zinc Oxide Nanorods Grown on Gallium Nitride Substrate

2016 ◽  
Vol 19 (4) ◽  
pp. 181-183 ◽  
Author(s):  
Tzu-Yi Yu ◽  
Yi Cian Chen ◽  
Wang Ting Chiu ◽  
Yang Luo ◽  
Sheng Shin Wang ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Zno Nanorods ◽  
Nano Particles ◽  
Zinc Oxide Nanorods ◽  
X Ray Diffraction ◽  
Thermal Methods ◽  
X Ray ◽  
Oxide Nanorods ◽  
Different Temperatures ◽  
Multiple Material

In this study, we address process how the ZnO nanorods were deposited on GaN substrates with spin-coating by using the hydro-thermal methods. After ZnO was spin coated, the samples were annealed with different temperatures to incorporate with Au nano particles. Multiple material analyses, such as the field emission scanning electron microscopy (FESEM), the energy dispersive X-ray spectroscopy (EDX) and the X-ray diffraction (XRD) analyses were carried out to characterize the Au nanoparticles/ZnO nanorods/GaN nanocomposites.

scholarly journals Effect of neodymium doping on structural, microscopic and electrical properties of barium phosphate system

2014 ◽  
Vol 04 (02) ◽  
pp. 1450007 ◽  
Author(s):  
Shivani Suri ◽  
Vishal Singh ◽  
K. K. Bamzai
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Stoichiometric Composition ◽  
Solution Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Solution ◽  
Flower Type ◽  
Phosphate System

Neodymium-doped barium phosphate (NdBP) was prepared as single crystal by room temperature solution technique known as gel encapsulation technique. Single crystal X-ray diffraction shows that the crystal belongs to orthorhombic system. The flower type morphology was observed by scanning electron microscope (SEM) and the stoichiometric composition of the prepared crystal was observed by energy dispersive X-ray analysis (EDAX). The presence of functional group and other groups was studied by Fourier transform infrared spectroscopy (FTIR). The electrical properties of these materials like dielectric constant (ε′), dielectric loss (tanδ) and ac conductivity [ln(σac)] was studied at different temperatures ranging from 40°C to 420°C in the frequency range of 5 kHz to 1 MHz. The activation energy values decreases with increase in frequency suggesting that the conduction mechanism is because of hopping of charge carriers.

Experimental and Numerical Study on Dynamic Properties of Viscoelastic Microvibration Damper Considering Temperature and Frequency Effects

2016 ◽  
Vol 11 (6) ◽  
Author(s):  
Chao Xu ◽  
Zhao-Dong Xu ◽  
Teng Ge ◽  
Ya-Xin Liao
Keyword(s):  
Loss Factor ◽  
Numerical Study ◽  
Dynamic Properties ◽  
Frequency Effect ◽  
Solid Model ◽  
Temperature Dependent ◽  
Frequency Effects ◽  
Proposed Model ◽  
Different Temperatures ◽  
Increasing Temperature

This work presents an experimental and numerical study on the dynamic properties of viscoelastic (VE) microvibration damper under microvibration conditions at different frequencies and temperatures. The experimental results show that the storage modulus and the loss factor of VE microvibration damper both increase with increasing frequency but decrease with increasing temperature. To explicitly and accurately represent the temperature and frequency effects on the dynamic properties of VE microvibration damper, a modified standard solid model based on a phenomenological model and chain network model is proposed. A Gaussian chain spring and a temperature-dependent dashpot are employed to reflect the temperature effect in the model, and the frequency effect is considered with the nature of the standard solid model. Then, the proposed model is verified by comparing the numerical results with the experimental data. The results show that the proposed model can accurately describe the dynamic properties of VE microvibration damper at different temperatures and frequencies.

Magnetic Hardening of Mechanichally Alloyed SmFe11−xCoxTi

1999 ◽  
Vol 581 ◽  
Author(s):  
L. Bessais ◽  
C. Djega-Mariadassou
Keyword(s):  
Heat Treatment ◽  
Rietveld Method ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Different Temperatures ◽  
Magnetic Hardening ◽  
Property Changes ◽  
Nanocrystalline Phases

ABSTRACTMechanical alloying of ternary SmFe11−xCoxTi (x = 0, 0.5, 1, 1.5, 2) alloys was carried out under an Ar atmosphere. Milled samples were annealed for 30 min in a vacuum at different temperatures Ta from 650 °C to 1150 °C. The effects of heat treatment, on structure and magnetic property changes, have been investigated by means of x-ray diffraction using the Rietveld method, Mössbauer spectroscopy and differential sample magnetometer. Tetragonal ThMn12-type structure is observed for samples annealed at Ta > 900 °C. For 650<Ta<800 °C the TbCu7 type phase was identified as the major phase. Between these two regions a mixture of TbCu7 and ThMn12-type nanocrystalline phases is obtained with a maximum of the coercive field Hc (Hc > 5kOe). The Mössbauer spectra relative to the hexagonal phase show sextuplets broadened by the statistical occupancies of the iron sites. An enhancement of the magnetic properties results from the Co substitution.

scholarly journals Temperature and Field Dependence of Field Grading Tubes for Medium Voltage XLPE Cable Joints

2017 ◽  
Author(s):  
Frank Mauseth ◽  
Henrik Enoksen ◽  
Sverre Hvidsten
Keyword(s):  
Electrical Properties ◽  
Normal Operation ◽  
Temperature Dependent ◽  
Depolarization Current ◽  
Electrical Fields ◽  
Xlpe Cable ◽  
Medium Voltage ◽  
Stress Control ◽  
Different Temperatures ◽  
Polarity Change

<p>In Norway it has been observed that many medium voltage (12 and 24 kV) cable sections with heat shrink joints have suffered from overheating often causing failure during service. The overheating is due to a bad metallic connection between the aluminium conductors in the joint. This is especially observed for XLPE cables installed in the 80’s, which constitutes a significant part of the installed cables in the network.<br />This paper is part of a work to elucidate the mechanisms causing a low insulation resistance of MV cable joints. As a bad metallic connection can result in local high temperatures during normal operation, the properties of a heat shrink stress control tubes commonly used in such joints has been characterized at temperatures around the melting peak of the material that is just above the maximum service temperature of 90 °C for XLPE cables. The main purpose of this paper is to examine the effect of these temperatures on the electrical properties of the field grading material. Here, the electrical properties have been characterized by time domain dielectric response measurements at different temperatures and axial electrical fields. <br />The results show that the conductivity of the stress control tube is temperature dependent. Also, a polarity change in the depolarization current at higher electrical field strengths was observed.</p>

scholarly journals Chlorapatite Derived from Fish Scales

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1129
Author(s):  
Luyara de Almeida Cavalcante ◽  
Laís Sibaldo Ribeiro ◽  
Mitsuo Lopes Takeno ◽  
Pedro Tupa Pandava Aum ◽  
Yanne Katiussy Pereira Gurgel Aum ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Xrd Analysis ◽  
Fish Scales ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Arapaima Gigas ◽  
Treated Fish ◽  
Different Temperatures ◽  
Increasing Temperature

The present work demonstrates the production of chlorapatite (ClAp) through thermal decomposition of chemically treated fish scales, originating from an Amazon fish species (Arapaima gigas). The scales were treated with hydrochloric acid (HCl) solution for deproteinization. Afterwards, the solution was neutralized by sodium hydroxide (NaOH) treatment to obtain an apatite-rich slurry. The heat treatment was carried out at different temperatures including 600 °C, 800 °C, and 1000 °C. The powders obtained were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The XRD analysis and FTIR spectra confirmed the incorporation of chlorine into the apatite structure. The FTIR results showed absorption bands relative to the OH–, PO43− functional groups which are a characteristic of chlorapatite. Moreover, the intensity of the OH–Cl elongation could be observed. Chlorapatite Ca5(PO4)3Cl, NaCl, and NaCaPO4 phases were identified, achieving up to 87.4 wt% for ClAp. The SEM observations show that with increasing temperature, the ClAp obtained consists of slightly larger, more crystalline grains. Furthermore, the grains ranged in size, between 1-5 μm and ClAp1000 sample recorded crystallinity of 84.27%. ClAp and NaCaPO4 can be used in electronics as phosphor materials due to their luminescence and biomedical applications.

ZnO Nanowalls/Si Substrate Heterojunction Assembly: Morphological, Optical and Electrical Properties

2020 ◽  
Vol 15 (5) ◽  
pp. 586-591
Author(s):  
Yas Al-Hadeethi ◽  
Ahmad Umar ◽  
Saleh H. Al-Heniti ◽  
Bahaaudin M. Raffah ◽  
Rashad I. Badran
Keyword(s):  
Electrical Properties ◽  
Room Temperature ◽  
Forward Bias ◽  
Three Dimensional ◽  
Zinc Powder ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Irregular Shapes ◽  
Heterojunction Device ◽  
Bias Condition

In this paper, a film of n-ZnO nanowalls was deposited over p-silicon (Si) substrate by thermally evaporating metallic zinc powder in oxygen gas environment. Several techniques were used to examine various properties of prepared ZnO nanowalls. The morphological study confirmed that the grown ZnO film possesses nanowalls shaped morphologies containing three dimensional (3D) interconnected nanowalls forming large voids with irregular shapes. Interestingly, whole Si substrate was covered with nanowalls shaped morphologies. The structural characterizations examined by x-ray diffraction (XRD) confirmed that the deposited nanowalls possess wurtzite hexagonal crystal structure. The presence of a strong UV and suppressed green emissions at room-temperature photoluminescence (PL) spectrum exhibited good optical properties of the deposited nanowalls. The electrical properties of the deposited n-ZnO nanowalls over p-silicon substrate assembly was examined in both forward and reverse bias conditions at room-temperature. The fabricated heterojunction device exhibits a standard rectifying behavior which manifests itself in an exponential increase of the current with increase in voltage at forward bias condition. Also, it has a good quality factor similar to an ideal diode.

Morphology, Opto-Electronic and Dielectric Properties of Vacuum Sublimed CuPc Based Thin Films

2019 ◽  
Vol 14 (11) ◽  
pp. 1523-1531
Author(s):  
Manjit Kaur ◽  
Rakesh Dogra ◽  
Narinder Arora ◽  
Navjeet Sharma ◽  
Rajesh Kumar
Keyword(s):  
Thin Films ◽  
Hole Mobility ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Optical Band Gaps ◽  
Different Temperatures ◽  
Evaporation Technique ◽  
Uv Visible ◽  
Substrate Temperatures

AC transport properties and dielectric response of sandwich geometry (Ag/CuPc/Ag) of CuPc(CuPc) thin films deposited using thermal evaporation technique have been studied within frequency range 1 Hz–10 KHz and in temperature range 303–383 K. Scanning electron microscope (SEM) investigations of these films reveal fiber like morphology. Crystalline natures of CuPc films have been characterized using X-ray diffraction for different temperatures. The molecular orientations in films for different substrate temperatures have been confirmed by Raman spectroscopy. The optical band gaps calculated from the UV–Visible absorption spectra is found to lie in the range 3.01–3.15 eV. Electrical conductivity of CuPc films increases with increase of temperature. The hole mobility values of CuPc films at different temperatures have been calculated using negative differential susceptance (–ΔB) technique. Both capacitance and dielectric constant have been found to decrease with the increase of frequency and temperature.

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