139,348 research outputs found
The effect of graphene oxide content on the photocatalytic activity of (ZnCdS/MnFe2O4/GO) nanocomposite
No full textNovel ternary Zinc cadmium sulfate/Manganese ferrite/Graphene oxide (ZnCdS/MnFe 2 O 4 /GO) nanocomposites were synthesized via a hydrothermal process in this study, with a focus on optimizing the graphene oxide (GO) content. Characterization techniques such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FE -SEM), UV - visible spectroscopy, photoluminescence (PL) spectroscopy, and N 2 physisorption were employed. The investigation revealed that nanocomposites with 3 wt% GO content exhibited superior adsorption capacity and visible-light photocatalytic activity for the removal of Methylene blue (MB) from wastewater. The ZnCdS/MnFe 2 O 4 /GO 3 % composite demonstrated exceptional stability and efficiency, achieving nearly 96 % MB removal within 220 min. Moreover, the ZnCdS/MnFe 2 O 4 /GO 3 % nanocomposites displayed promising reusability with sustained photocatalytic activity over multiple degradation-regeneration cycles. These findings highlight the potential of ternary GO/ZnCdS/MnFe 2 O 4 nanocomposites as effective photocatalysts for the practical remediation of organic pollutants in wastewater systems
The Structural and Electrical Properties of the Au/n-Si (MS) Diodes with Nanocomposites Interlayer (Ag-Doped ZnO/PVP) by Using the Simple Ultrasound-Assisted Method
No full text© 1963-2012 IEEE.In this paper, Au/Ag-doped ZnO/polyvinyl pyrrolidone (PVP)/n-Si [metal-polymer-semiconductor (MPS)] Schottky Barrier Diodes (SBDs) were fabricated. The structural properties of the Ag-doped ZnO/PVP nanocomposites have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analyses. The XRD pattern indicated that the samples have high purity ZnO and Ag materials and have not observed other peaks. The mean crystallite size of nanoparticles was calculated using Debye-Scherer's equation and the measured sizes reveal clearly the formation of small nanocrystals. The SEM and EDX results show the sheetlike ZnO nanostructures and also confirm the presence of Zn, O, and Ag materials with the nonstoichiometric ratio. The values of ideality factor (n), zero-bias barrier height (ΦB0), and series resistance (RS) of the MPS-type SBD were obtained from both the thermionic emission (TE) and Cheung function and the observed some discrepancy between them was due to the voltage-dependent of these parameters and the nature of the calculation method. The value of surface states (Nss) was changed from 2.2 × 1013 eV-1 cm-2 at (Ec ? 0.44) eV to 8.19 × 1012 eV-1 cm-2 at (Ec ? 0.69) eV and these values are more suitable for the MPS-type SBD. The values of doping-donor atoms (ND), depletion layer width (WD), and φB [capacitancevoltage (C?V )] were obtained from the reverse bias C-2?V plot as a function of frequency. While the value of ND decreases with increasing frequency,WD increases almost as exponentially. However, there is a good relationship between φB (C?V ) and ln(f )
C-V-f and G/ω-V-f characteristics of Au/(In2O3-PVP)/n-Si (MPS) structure
No full text© 2020 Elsevier B.V.In this work, the indium oxide (In2O3)-polyvinylpyrrolidone(PVP) film on the n-Si substrate was coated by a spin coating method. Thus, the Au/(In2O3-PVP)/n-Si metal-polymer-semiconductor (MPS) structure was fabricated. The capacitance/conductance-voltage-frequency (C-V-f and G/ω-V-f) characteristics of the fabricated MPS structure have been analyzed in the frequency range of 10 kHz - 1 MHz. The series resistance (Rs) and interface state density (Nss) value of the MPS structure were determined by using the conductance and Hill-Coleman method, respectively. In addition, other electronic parameters such as the diffusion potential, barrier height, depletion layer width, and surface potential were extracted from the C−2-V characteristics
Frequency Response of C-V and G/omega-V Characteristics of Au/(Nanographite-doped PVP)/n-Si Structures
No full textThis paper reports that frequency response on profile of C–V–ƒ and G/ω–V–ƒ characteristics of spin-coated nanographite (NG)-doped polyvinylpyrrolidone (PVP)/n-Si structures in a wide frequency (1 kHz–5 MHz) and voltage (± 3 V) ranges at room temperature. Hereby, the basic parameters of the structure such as diffusion potential (VD), doping donor density (ND), Fermi energy level (EF), maximum electric field (Em), depletion layer thickness (Wd), and barrier height (ΦB) are derived by using the intercept and slope of C−2–V–ƒ plot for each frequency. Additionally, the energy density distribution of surface states (Nss) and their relaxation time values (τ) are also attained from the conduction method and their values are found as 4.999 × 1012 eV−1 cm−2 and 2.92 µs at 0.452 eV, and 3.857 × 1012 eV−1 cm−2 and 164 µs at 0.625 eV, respectively. The lower Nss values are the consequence of passivation effect of the used nanographite (NG)-PVP polymer interlayer. As a result, the polymer interlayer based nanographite (NG)-PVP is candidate instead of the widely used oxide/insulator layer for the purpose of decreasing the surface states or dislocations
Centre-based hard clustering algorithms for Y-STR data / Ali Seman, Zainab Abu Bakar and Azizian Mohd. Sapawi
No full textThis paper presents Centre-based hard clustering approaches for clustering Y-STR data. Two classical partitioning techniques: Centroid-based partitioning technique and Representative object-based partitioning technique are evaluated. The k-Means and the k-Modes algorithms are the fundamental algorithms for the centroid-based partitioning technique, whereas the k-Medoids is a representative object-based partitioning technique. The three algorithms above are experimented and evaluated in partitioning Y-STR haplogroups and Y-STR Surname data. The overall results show that the centroid-based partitioning technique is better than the representative object-based partitioning technique in clustering Y-STR data
Facile ultrasound-assisted and microwave-assisted methods for preparation of Bi2S3-PVA nanostructures: exploring their pertinent structural and optical properties and comparative studies on the electrical, properties of Au/(Bi2S3-PVA)/n-Si Schottky structure
No full textOn the conduction mechanisms of Au/(Cu2O–CuO–PVA)/n-Si (MPS) Schottky barrier diodes (SBDs) using current–voltage–temperature (I–V–T) characteristics
No full text© 2017, Springer Science+Business Media, LLC.The temperature effect on the conduction mechanism of Au/Cu2O–CuO–PVA/n-Si (MPS) type Schottky barrier diodes (SBDs) have been investigated in detail in the wide temperature range of 100–380 K by using the forward bias current–voltage (I–V) measurements. It is observed that the semi logarithmic forward bias I–V plots have two distinct linear regions with different slopes for each temperature. These regions are called low bias region (LBR) and moderate bias region (MBR), respectively. The LBR and MBR correspond to (0.6–1.04 V) and (1.10–1.65 V) bias voltages, respectively. Main diode parameters such as reverse saturation current (I0), ideality factor (n) and zero-bias barrier height (Φb0) were calculated for these two regions. It is observed that the values of Φb0 increased as the values of n decreased with the increasing temperature and such behavior of Φb0 and n with temperature was attributed to the barrier inhomogeneities by assuming Gaussian distribution (GD) at the M/S interface. The Φb0 versus n and q/2kT plots were drawn to get an evidence of the GD. These two plots also have two linear regions at LBR and MBR. These regions are called the low temperature region (LTR) and high temperature region (HTR). Thus the mean values of barrier height (BH) and standard deviation (σs) were obtained by using the intercept and slope of these plots. After that, the conventional Richardson plot was drawn [(Ln(I0/T2) − q2σs 2/2k2T2) vs. q/kT] and it also has two linear regions. The main values of BH and effective Richardson constant (A*) were obtained from the slope and intercept of these plots. These values are found as 0.82 eV and 110.7 A/cm2 K2 for LTR and 1.53 eV and 115.5 A/cm2 K2 for HTR in the LBR and 0.77 eV and 111.9 A/cm2 K2 for LTR and 1.26 eV and 133.9 A/cm2 K2 for HTR in the MBR, respectively. The obtained values of A* are in good agreement with their theoretic values (112 A/cm2 K2) especially for HTR. Thus, the I–V–T characteristics of MPS type SBDs are successfully explained by the double GD model. Besides, the interface state density (Nss) of the MPS diode was calculated from forward-bias I–V measurements
Series resistance and interface states effects on the C–V and G/w–V characteristics in Au/(Co3O4-doped PVA)/n-Si structures at room temperature
No full text© 2017, Springer Science+Business Media New York.Microwave-assisted method has been used for preparation of Co3O4 nanopowders. Then, Co3O4–doped polyvinyl alcohol (PVA) composites are deposited on n-Si wafer using spin coating method. The main electrical parameters of the Au/(Co3O4-doped PVA)/n-Si type Schotkky barrier diodes (SBDs) have been investigated by capacitance–voltage-frequency (C–V-f) and conductance–voltage-frequency (G/ω–V-f) measurements at room temperature and they were performed in the frequency range of 2 kHz–2 MHz and at (±4.5 V) by 50 mV steps. The XRD pattern of the as-prepared sample show that all diffraction peaks appeared in this pattern match very well with ICDD data and they can be readily indexed to the Co3O4 nanostructures, no other peaks were observed, which indicates the high purity of the sample. The effects of (Co3O4-doped PVA), series resistance (Rs) and surface states (Nss) on electrical characteristics have been investigated in detail. In order to eliminate the effect of Rs on high frequencies these measurements, the measured Cm and Gm/ω values were adjustment. The high values of Nss at low frequencies are responsible for the non-ideal behavior of C–V and G/ω–V characteristics. The obtained value of ND exponentially decreases; the value of ΦB (C–V) exponentially increases with increases frequency. Such behavior of ND and ΦB (C–V) are expected behavior and it is attributed to the particular density distribution of Nss, polarization processes and interfacial layer. Experimental results show that the C–V and G/ω–V characteristics of SBDs are affected not only in Nss and Rs but also interfacial polymer (Co3O4-doped PVA) layer
CORRELATION BETWEEN WETTABILITY AND OPTICAL PROPERTIES OF SILVER-BASED THIN FILMS PREPARED BY SPUTTERING METHOD WITH INCLINED SUBSTRATE AND SHADOWING EFFECT
No full text In this work, various silver-based thin films were prepared by sputtering method with inclined substrates in the presence of shadowing object. The morphology and structural and optical properties of the prepared thin films were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS), respectively. The wettability of films was investigated by measuring contact angles of the films. The obtained results show that by increasing shadowing effect, a decrease in contact angle of the prepared samples is observed. Bruggeman homogenization simulation method was applied to describe the film structures. The theoretical part and simulation using Bruggeman homogenization confirm the experimental findings and show the best possible agreements. Finally, an increase in contact angle of the prepared thin films with high porosity and high surface roughness was observed. In films with silver–silver oxide compositions, the higher contribution of oxide part in the structure of the films leads to the hydrophilicity of the surface. </jats:p
Facile ultrasound-assisted and microwave-assisted methods for preparation of Bi2S3-PVA nanostructures: exploring their pertinent structural and optical properties and comparative studies on the electrical, properties of Au/(Bi2S3-PVA)/n-Si Schottky structure
No full text© 2017, Springer Science+Business Media, LLC.Polyvinyl alcohol capped Bi2S3 semiconductor nanocrystals were prepared by microwave-assisted and ultrasound-assisted methods after heat treatment in open air at 300 °C for 1 h. The optical, structural and morphological properties of them have been characterized by XRD, UV–Visible, FT-IR, SEM, TEM techniques. The XRD pattern shows the formation of nano-crystalline Bi2S3 and the UV–Vis spectroscopy results show a blue shift of about 1.5 and 1.6 eV for microwave and ultrasound-assisted methods, respectively. These values are due to the confinement of very small nanostructures. In order to determine electrical characteristics, the SBDs measurements of current, capacitance and conductance versus voltage (I–V, C–V, and G/ω−V) were performed at room temperature. Fermi energy level (EF), donor doping atoms (ND), and barrier height (ΦB) values were obtained by C−2–V plots at reverse biases. The voltage dependent profile of series resistance (Rs) was extracted by the Nicollian-Brews method. The energy dependent profiles of Nss were also obtained from the forward bias I–V data by considering voltage dependent ideality factor (n) and effective barrier height (Φe) for two type diodes. The values of the rectifying ratio (RR) and BH for the ultrasound -assisted interlayer are found greater than the microwave-assisted interlayer. The double-logarithmic I–V plots show three distinct linear regimes which are corresponding to low, intermediate and high forward biases for two structures and in these regions, the dominant current-transport was found via trap-charge limited current and space-charge-limited-current mechanisms, respectively. The value of BH obtained from the forward bias I–V is lower than at about EF from the reverse bias C–V measurement because of the nature of measurement techniques. These observations of low leakage current and higher RR, Rsh and BH for ultrasound-assisted interlayer MPS structure was confirmed that it has good performance when compared to the microwave-assisted interlayer MPS structure
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