Effect Of Doping Concentration Research Articles

Enhanced electrical reliability of Zr‐doped BaTiO3 nanoceramics: First‐principle calculations and experimental studies

AbstractWith the miniaturization of multilayer ceramic capacitors (MLCCs) and the increase of electric field on single‐layer dielectrics, it is essential for the development of nanograin high‐reliability dielectric materials. In this work, Zr‐doped BaTiO3‐based ceramics with an average grain size of 130–150 nm were prepared by a chemical coating method. The effects and intrinsic mechanisms of Zr concentration on microstructure, dielectric properties, and reliability were systematically investigated by theoretical calculations and experiments. Zr additives lower the migration barrier of the dopants, which consequently contributes to the formation of thick shell layers in the core‐shell structure and grain growth, affecting the temperature stability and DC bias characteristics of the dielectric constant. Owing to the large change rate of the Zr–O bond length, the introduction of Zr increases the migration barrier of oxygen vacancies. However, the decrease in the effective doping concentration of the shell part and the reduction in the number of grain boundaries of ceramics with high Zr content have a weakening effect on the inhibition of oxygen vacancy migration. An appropriate amount of Zr doping can adjust the dielectric properties and improve the reliability of BaTiO3‐based ceramics. This study provides a theoretical reference for the design of high‐quality MLCCs.

Exploring the electronic properties of doped zirconia for enhanced optoelectronic applications: A quantum chemical approach

Zirconia (ZrO2) is a versatile material with applications in various fields due to its exceptional mechanical strength, thermal stability, and chemical resistance. In recent years, interest has surged in utilizing doped ZrO2 as photocatalysts. This study investigates the electronic properties of ZrO2 upon doping with non-metal elements sulfur (S), selenium (Se), and tellurium (Te) using first-principle calculations. The effects of different doping concentrations on the band structure and density of states (DOS) have been examined. Calculations using GGA show significant reductions in the band gap upon doping, indicating potential for improved optoelectronic performance. Specifically, using accurate DFT + U approach we found that doping ZrO2 with 25 % S led to a band gap reduction from 5.4 eV to 1.2 eV, demonstrating promising result for photovoltaic applications. This study provides valuable insights into the electronic properties of doped ZrO2 (ZrO2-xQx, Q = S, Se and Te, x = 0.25, 0.5 and 2) paving the way for tailored applications in various technological domains.

The effect of Mn doping on the electrical and magnetic properties of Cr2Te3 thin films

Mn doped Cr2-xMnxTe3 thin films were prepared by molecular beam epitaxy technology. The effect of Mn doping concentration on the structural, morphological, electrical and magnetic performance of Cr2Te3 thin films were detailed analyzed. By varying the beam current of the Mn source, it is found that Mn can be doped into the Cr2Te3 thin film when the Mn source temperature is lower than 700 ℃, while the Mn tends to bind with Te as MnTe crystal for Mn source temperature higher than 700 ℃. Cr2-xMnxTe3 films all exhibt strong ferromagnetism with a Curie temperature of around 175 K. The magnetization of the films decreases with increasing Mn doping concentration. A notable negative magnetoresistance effect is observed with the highest MR ratio about −60 % in the vicinity of the Curie temperature. A clear topological Hall signal was observed in the sample with a Mn source temperature of 700 ℃ at low temperature (2 K). These results imply that the electrical and magnetic properties of Cr2Te3 materials can be effectively controlled by doping to meet the practical needs of different fields.

Effect of Dopant Concentration on Luminescence Properties of Na3Ca2(SO4)3F: RE (RE = Eu3+, Dy3+) Phosphor for Solid-State Lighting.

A fluoride material phosphor doped with rare earth ions Eu3+ and Dy3+ was studied for its photoluminescence (PL) properties. The material was synthesized using a combustion method and characterized using X-ray diffraction (XRD) and PL techniques. The Na3Ca2(SO4)3F: Eu3+ phosphor exhibits two distinct peaks at 593 nm (orange) and 615 nm (red) at an excitation wavelength of 395 nm. The PL excitation spectrum of the Na3Ca2(SO4)3F: Dy3+ phosphor showed series of peaks, corresponding to the 4f → 4f transitions of Dy3+ ions. Under 350-nm excitation, the PL emission spectrum revealed two prominent bands one at 483 nm (blue region) due to the 4F₉/₂ → 6H₁₅/₂ transition, and another at 573 nm (yellow region) resulting from the 4F₉/₂ → 6H₁₃/₂ transition. These blue and yellow emissions suggest potential applications in solid-state lighting, particularly for mercury-free excitation sources. Rare earth-doped Eu3+/Dy3+ materials exhibit highly efficient PL properties, making them suitable candidates for white light-emitting diodes (LEDs) or other solid-state lighting phosphors.

Engineering ceria oxide with nickel doping and rich oxygen vacancies for enhanced electrocatalytic degradation of aromatic organics

Aromatic dyes are widely applicable in the textile, leather, and ink industries yet receive serious contamination issues to water bodies, soil, and even air. Herein, we develop an efficient electrocatalytic oxidation method for degrading aromatic dyes via developing supportive CeO2-based electrode materials decorating with highly dispersive Ni and rich oxygen vacancies. The decorating Ni species are in situ converted from a composite of CeO2 nanocrystals and formamide-derived polyaminoimidazole (PAI)-coordinated Ni to ensure the high dispersion of Ni species. The decomposition of PAI ligands also helps to create the localized reductive atmosphere for the generation of rich surface oxygen vacancies, which further benefits the enhancement of electronic conductivity and charge transport ability. The effects of Ni doping concentrations, Rhodamine B (RhB, as a simulating aromatic dye) concentrations, pH of RhB solution, types and concentrations of electrolytes, and working current densities on the degradation performance are comprehensively investigated. Electrocatalytic measurements reveal that the CeO2 catalyst with optimal Ni concentration and fine single-crystal sizes of 5.5 ± 0.03 nm (termed as Ni0.025-CeO2-x) exhibits very promising degradation efficiency (96.9 %) and structural durability (repeated use for 5 cycles with limited activity decrease).

Ce-doped ZnO nanonails synthesized by a simple thermal evaporation method for photocatalytic degradation

One-dimensional (1D) nanomaterials have garnered significant scientific and technological attention due to their potential applications in electronics devices, gas sensing, energy conversion, and photocatalysis. However, the development of a simple and low-cost technique for 1D nanostructure synthesis remains a challenge. The doping of ZnO nanostructures has proven to be an effective way to improve their internal properties. In this work, one-dimensional ZnO and Ce-doped ZnO nanorods and nanonails were synthesized by a simple thermal evaporation method using different weight ratios of ZnS and CeO2 precursor powders in a catalyst-free process. The effects of cerium doping concentration on the structural, morphological, and optical properties of the as-prepared samples were investigated. XRD analysis confirmed that the crystal structure was converted from the cubic ZnS phase to the hexagonal ZnO phase with increasing annealing temperatures. The UV–Vis spectra showed that the optical absorption edge of Ce-doped ZnO samples was slightly red-shifted. Additionally, the band gap energy decreases with increasing cerium concentration. SEM images showed that the morphology of the structures obtained changed from nanorods to nanonails as the Ce content increased. The incorporation of Ce ions into the ZnO matrix has been successfully confirmed by HRTEM, Raman, and EDX analysis. Photocatalytic activity studies showed that Ce-doped ZnO samples exhibited significantly enhanced photocatalytic performance compared to pure ZnO for the degradation of rhodamine B under UV radiation. These results may suggest the use of heterogeneous photocatalysis as an efficient, cheap, and environment-friendly alternative for the removal of pollutants from water and the use of Ce-doped ZnO as a promising candidate.

Novel multi-mode anti-counterfeiting encryption material of CaAl12O19:Eu, Er with multi-color down-conversion luminescence, up-conversion luminescence, dynamic luminescence, and photochromism

Multi-mode dynamic anti-counterfeiting materials can provide complex anti-counterfeiting performance and ensure the anti-counterfeiting strategy becomes more secure. Herein, a new type of multi-mode anti-counterfeiting encryption material of CaAl12O19:Eu, Er with different Er doping concentration was developed by sol–gel method. Interestingly, the CaAl12O19:Eu, Er phosphor and its composite have multi-mode anti-counterfeiting characteristics of multi-color down-conversion luminescence, up-conversion luminescence, dynamic luminescence, and photochromism. Effect of different Er doping concentration on the down-conversion luminescence, up-conversion luminescence, dynamic luminescence, and photochromism of CaAl12O19:Eu, Er was systematically investigated, and the relevant mechanisms were discussed. These anti-counterfeiting features can be simultaneously applied in both bright and dark fields, which can achieve high-level anti-counterfeiting in both spatial and temporal dimensions. The CaAl12O19:Eu, Er phosphors cannot be easily replaced by other materials with the same anti-counterfeiting properties. They display good application foreground in the field of anti-counterfeiting encryption.

Donor Defect Induced Ferromagnetism in Nb‐Doped ZnO Thin Films Grown by RF Magnetron Sputtering

The effect of Nb doping concentration (0, 1, 2, and 4 at. %) on donor defect‐induced ferromagnetism in ZnO thin films is investigated. The films are deposited on Si(111) substrates utilizing the radio frequency magnetron sputtering. X‐ray diffraction pattern unveils that the films show a pronounced orientation along the (002) direction. The relative intensities of defect‐related bands with that of the ultraviolet band from photoluminescence (PL) spectra show that 2 at. % Nb doping results in a greater number of donor defects (Zni+ and VO+) in the ZnO lattice. The parameters extracted from the electron paramagnetic resonance spectra follow a similar trend. The results from vibrating sample magnetometer measurement indicate that pure ZnO displays diamagnetic nature, whereas Nb‐doped ZnO exhibits a ferromagnetic nature. The saturation magnetization value is found highest for 2 at. % Nb doping, which correlates with the presence of a greater number of donor defects, as supported by the PL and electron paramagnetic resonance results. Images obtained from atomic force microscopy show that the surface roughness of the ZnO thin film reduces upon Nb doping. X‐ray photoelectron spectroscopy validates that Nb is doped in 2 at. % Nb‐doped ZnO thin film with Nb oxidation state of +5.

Physical properties of Pr3+ substituted zinc spinel (ZnPrxFe2−xO4) nanoferrites synthesized via sol–gel auto-combustion route

Spinel ferrites, a group of metal oxides, have garnered significant attention in the recent decade due to their high demand for numerous applications, including data storage and microwave device applications. In this context, we studied the effect of different doping concentrations of large Pr ions on the physicochemical properties of spinel lattice, such as dielectric and magnetic properties. In this research, we successfully fabricated a series of praseodymium ion-doped zinc spinel ferrites ZnPrxFe2-xO4 nanoparticles 0.00≤x≤0.20 via a simple and economical sol–gel auto-combustion approach. XRD (X-ray Diffraction Analysis) and FTIR investigations validate the presence of a cubical phase, with the crystallite size varying between 11 nm to 19 nm depending on the amount of Pr present. The Scherrer method, Williamson-Hall analysis (WH), and size-strain plot method (SSP) were investigated the correlation of crystalize size. The SSP approach has a better correlation coefficient than the WH method. Transmission electron microscopy TEM shows that the prepared material possessed the cubic and spherical symmetry. The significant variation in electrical parameters was discussed at an applied frequency ranging from 1 MHz to 3 GHz. The dielectric constant is approximately constant in low-frequency regions then relaxation peaks were observed at nearly 1.4 GHz and 2.2 GHz. The dielectric constant and complex dielectric constant of these samples dropped as the praseodymium content increased. Investigations regarding the magnetic properties were carried out using a vibrating sample magnetometer (VSM) at −23 k Oe to +23 k Oe. Low coercivity and relaxation peaks at high frequencies suggest that this material may be suitable for core materials, microwave technologies and recording media.

The figure of merit improvement of (Sn, Co)–ZnO sprayed thin films for optoelectronic applications

Nanocrystalline zinc oxide (ZnO) has garnered significant attention from researchers and industries due to its superior properties as an optoelectronic material, particularly in solar cells as a transparent electrode. Doping, especially with tin (Sn) and co-doping with tin and cobalt (Co), can refine its optoelectronic properties. In this manuscript, we report on the optoelectronic properties of undoped ZnO thin films, as well as those doped with Sn and/or Co, elaborated using a simple chemical pneumatic spray pyrolysis method on glass substrates. A 1 % Sn doping concentration was used, with Co doping concentrations of 0 %, 0.5 %, and 1 %. The effects of Sn and/or Co doping concentration on the structure, morphology, optical, and electrical properties of nanocrystalline ZnO were studied using X-ray diffractometer (XRD), Raman spectroscopy, Field emission scanning electron microscopy (FESEM), UV–Vis–NIR spectroscopy and Hall effect measurements. All the films studied exhibit wurtzite ZnO structures with a predominant (002) orientation and no secondary phase, as confirmed by X-ray diffraction (XRD) analysis. The Raman spectroscopy also reveals the presence of a wurtzite structure in all the films. The FESEM images reveal the kind and concentration of the dopants significantly influenced the surface morphology of the films. The elemental analysis with energy dispersive X-ray analysis (EDS) analysis successfully detected the doping of Sn and Co. The analysis of UV–Vis spectroscopy provide that the optical band gap for the undoped ZnO film is 3.25 eV. This band gap increases upon doping and co-doping, reaching a peak value of 3.30 eV for the Sn:Co (1 %:0.5 %) co-doped ZnO film. The ZnO film shows an improvement in the electrical resistivity upon doping and co-doping with low resistivity value of 1.95 × 10−2 Ω cm for the film (1%Sn, 0.5 % Co)–ZnO. The highest figure of merit (FOM) achieved is 1.41 × 10−4 Ω−1 for a ZnO thin film co-doped with (1 % Sn, 0.5 % Co). The existence of (1 % Sn, 0.5 % Co) film with improved optical gap, low electrical resistivity and high FOM supports its use in transparent conductive oxide applications.

Unveiling highly sensitive Dy3+ doped BaMgAl10O17 phosphor’s thermoluminescence trap features and temperature dependent luminescence for solid state lighting applications

This article explores the structural, morphological, thermoluminescence, and temperature-dependent emission properties of novel Dy3+ doped BaMgAl10O17(BAM-Dy) phosphors. Structural studies reveal that the phosphor has a similar structure to β-alumina. Rod-shaped interlinked surface morphology is a notable characteristic of the BAM-Dy samples. Incorporation of Dy3+ ions lead to the formation of distinct emission peaks (485 nm, 577 nm, and 635 nm) in the PL emission spectra. The effect of dopant concentration on the light output is crucial, and the highest PL intensity is observed for 1.5 mol% of Dy3+ concentration. The potential use of BAM-Dy phosphors for Gamma radiation detection and measurement is tested through thermoluminescence studies, which reveal high sensitivity, low threshold dose values, and exceptional response to low gamma doses, making them suitable for dosimetry applications. The investigation of trap parameters provides useful information about the number of traps, trapping mechanism, and trap energies, which is essential for in-depth study of synthesized phosphors for γ dosimetry application. The study of the effect of temperature on the luminescence behaviour is crucial for the application of phosphors in the light-emitting field. The BAM-Dy samples exhibit excellent thermal stability even at 210 °C, making them suitable for use in the field of White LEDs.

Performance parameters estimation of high speed Silicon/Germanium/InGaAsP avalanche photodiodes wide bandwidth capability in ultra high speed optical communication system

Abstract This paper has clarified the performance parameters estimation of high speed silicon/germanium/InGaAsP avalanche photodiodes wide bandwidth capability in ultrahigh speed optical communication system. The basic structure configuration of avalanche photodiode is clarified. The basic depletion region configuration schematic view is demonstrated. As well as the maximum electric field is indicated for impact ionization through avalanche photodiode in the presence of load. Various avalanche photo-detectors multiplication factor is clarified versus reverse bias voltage at room temperature. Different avalanche photo-detectors dark current is measured against avalanche photo-detectors volume at room temperature. Various avalanche photo-detectors effective doping concentration is demonstrated against ambient temperature variations. Si/Ge/InGaAsP avalanche photo-detectors excess noise factor is demonstrated versus the ionization ratio at room temperature (T = 300 K) and different ambient temperature (T = 350 K and T = 400 K). Various avalanche photo-detectors excess noise factor is measured clearly versus the multiplication factor at room temperature. Si/Ge/InGaAsP avalanche photo-detectors excess noise factor is demonstrated versus reverse bias voltage at room temperature. Si/Ge/InGaAsP avalanche photo-detectors noise equivalent power is clarified versus multiplication factor at room temperature. Various avalanche photo-detectors noise equivalent power is studied versus temperature variations. Si/Ge/InGaAsP avalanche photo-detectors sensitivity is measured in relation to the temperature variations. Different avalanche photo-detectors sensitivity is demonstrated in relation to reverse bias voltage variations at room temperature.

The effects of Hf-doping and thermal treatment on the resistive switching properties of rf magnetron sputtered Sm2(1-x)HfxCe2O7 thin films

The Sm2(1-x)HfxCe2O7 thin films were prepared via the RF sputtering, and the effects of different doping concentrations and thermal treatments on the resistive switching properties of Al/Sm2(1-x)HfxCe2O7/ITO devices were studied. The research indicates that at a HfO2 content of 0.05 mol%, the switching cycles can be increased from 1031 for undoped film to 1221, along with a Ron/Roff ratio > 101, and a retention time 104 s. By employing an annealing process at 300 °C, the device demonstrates extended endurance, enduring 2185 switching cycles, achieving a Ron/Roff ratio > 101, and boasting a retention time of 104 s, thereby showcasing excellent durability and data retention properties. The I–V characteristics are primarily influenced by the addition of Hf4+ ions and atomic rearrangement after thermal treatment. The conductive filaments are formed by oxygen vacancies and metal ion-assisted filaments in the Al/Sm2(1-x)HfxCe2O7/ITO device with x = 0.05 annealed at 300 °C. Moreover, the switching window can be enhanced to a Ron/Roff ratio of approximately 103 through post-metal annealing. This study suggests that Al/Sm2(1-x)HfxCe2O7/ITO devices hold promise as volatile memory materials.

Biogenic Ag-doped ZnO nanostructures induced cytotoxicity in luminal A and triple-negative human breast cancer cells.

Aim: To evaluate the apoptosis-inducing properties of undoped and silver-doped-zinc-oxide nanoparticles (SDZONs) synthesized using Boswellia serrata against MCF-7 (Luminal-A) and MDA-MB-231(Triple-negative) breast cancer cell lines.Methodology: Nanostructures were developed by facile biohydrothermal method and characterized by x-ray diffraction (XRD), Fourier transform infrared (FTIR), and high resolutiontransmission electron microscopy (HR-TEM). The comparative effect of doping and dose concentration of nanostructures on cytotoxicity was measured using MTT and trypan-blue-exclusion assay.Results: SDZONs exhibited greater cytotoxicity (20.71%, 27.31% cell viability) as compared with undoped nanostructures (35.81%, 37.08% cell viability) against MCF 7 and MDA-MB-231, respectively.Conclusion: The activity of biogenic nanostructures was highly dependent on doping, dose, and type of cell lines used. The novel biogenic SDZONs could be exploited as a promising, cost-effective, and environmentally benign strategy to curb breast cancer.

The effect of Mg doping concentration and annealing on the structure and luminescence properties of ZnO thin films

The effect of Mg doping concentration and annealing on the structure and luminescence properties of ZnO thin films

Effect of different doping concentrations of X (X = O, Se, Te) on the electronic and optical properties of single layer WS2

In this paper, we study the effects of different doping concentrations of O, Se, and Te atoms on the electronic structure and optical properties of single layer WS2 based on the density generalization theory of the first principles. The most stable structure. The system doped with Te atoms shows a shift from direct to indirect band gap, and the band gap of the system doped with Se atoms increases slightly. When investigating the optical properties, we also found that the absorption of light in each doped system mostly occurs in the ultraviolet region, and the absorption of light in the system doped with O atoms decreases, while the absorption of light in the system doped with Se and Te atoms changes with different frequencies. The reflectivity is higher than the intrinsic state.

Effects of Ta concentration on microstructure, optical and optoelectronic properties of Ga2O3:Ta films

Ga2O3 material possesses extensive application potential and research value. Doping other elements into intrinsic Ga2O3 is one of the common methods to enhance its performance and is also a hot research direction nowadays. In this paper, Ta element was introduced into Ga2O3 material, and Ga2O3:Ta thin films with different Ta doping concentrations were fabricated using a dual-target RF co-sputtering system. The effects of Ta doping concentration on microstructure, optical, and optoelectronic properties of the films were meticulously investigated, and the optimal Ta doping concentration was determined. XPS results reveal that Ta entered Ga2O3 lattice with a +5 oxidation state, and combined with EDS results, it is inferred that Ta successfully partially substitutes Ga. XRD and XPS results indicate that when the sputtering power of Ta2O5 is 30 W, corresponding to a Ta doping concentration of 2.39 at.%, the film exhibits enhanced crystallinity. The Ga2O3-based MSM detector prepared under this condition demonstrates superior stability and detection sensitivity. Additionally, it also exhibits stable photoresponse to 365 nm light. This work promotes the application of Ga2O3 material and provides new insights into improving the stability and performance of ultraviolet photodetectors.

Preparation, characterization, and antibacterial activity of Ni, Sn co-doped ZnO nanoparticles: Effect of Sn doping concentration

Ni, Sn co-doped ZnO nanoparticles have been prepared by chemical method at room temperature. The effects of Sn on the structural, morphological, optical, electrical, and anti-microbial properties of the prepared nanoparticles have been evaluated and discussed. The crystallite size and the unit cell properties have been influenced by the doping concentration of Sn. The addition of Sn enhances the texture coefficient of the nanoparticles. The optical band gap of the material is blue-shifted as the doping concentration of Sn increases. The prepared nanoparticles have high hole concentration than electron concentration. The nanoparticles became more transparent at high doping concentrations. The effect of Sn concentration against E. coli, S. aureus, and P. aeruginosa has been evaluated.

A study of the effect of cerium ion doping concentration on the structural, electrical, and thermoelectric properties of CaMnO3 nanoparticles

Abstract Universally, energy loss in the form of heat is predominant and this heat is irrecoverable waste heat that leads to global warming. Clean, green, eco-friendly, cost-effective, and renewable energy sources are the possible solutions for this energy crisis and global warming issues. Thermoelectric power generation is a promising technology by converting this irrecoverable waste heat directly into electricity without any greenhouse gas emission. Nanostructured CaMnO3 at various cerium concentrations have been successfully prepared by sol–gel hydrothermal method followed by annealing and sintering. Pure and doped samples were systematically characterized by DSC, powder XRD, RAMAN, SEM with EDAX and FTIR spectroscopy. Electrical and thermoelectrical measurements were carried out on the sintered pellets. The XRD analyses confirmed the formation of orthorhombic perovskite structure for all the samples and the average particle size lies in the range of 50–60 nm. FTIR analysis shows the presence of CaMnO3 nanoparticles without any impurities. The temperature dependence of physical properties was performed and analyzed between room temperature and 600 °C. Electrical resistivity strongly depends on the nature of substituent ions and negative values indicate that the electrons are major charge carriers. Large Seebeck coefficient value and high-power factor make Ca1−x Ce x MnO3 an efficient thermoelectric material for energy storage applications.

Effects of Rare-Earth Elements Doping on Micro-Structure and Fluorescence Performances of Fluorapatite

For purposes of optimizing the microstructure and fluorescence properties of rare-earth elements (REEs)-doped fluorapatites (FAps), various kinds of REEs (La, Pr, Sm, Eu, Gd, Ho, Er, and Yb) with the concentration of 2~20 mol.% have been inserted into the FAps framework via hydrothermal method, in order to investigate the influential mechanism of the REEs on the crystal structure, morphology, and fluorescence under the excitation of the near-ultraviolet light of the FAps. Experimental results show that the wavelength of the emitted light of the REEs-doped FAps is decided by the type of REEs. Unlike the Pr/Yb- and Ho-doped FAps and with the fluorescence of red and green emitted light, respectively, the Er-doped FAps show a blue light emission with wavelengths of 296, 401, and 505 nm, which is, moreover, different with the Eu-doped Faps, showing an orange light emission with wavelengths of 490, 594, and 697 nm. The emission luminous color is related to the lattice defects of the FAps doped with the various types and the effective doping concentration of the REEs. The luminous intensity increases with the increase in the effective doping concentration of the REEs. Nevertheless, the formation of rare-earth fluoride results in the decrease in the effective doping concentration of the REEs and the luminous intensity. The FAps with an effective doping concentration of 7 mol.% Er and 3 mol.% Eu show relative excellent fluorescence properties.