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First-principles calculations of opto-electronic properties of IIIAs (III = Al, Ga, In) under influence of spin–orbit interaction effects
摘要： In this article, we present first-principles calculations for structural and opto-electric properties of IIIAs (III = Al, Ga, In) in the zinc-blende phase. Our calculations are based on the full potential-linearized augmented plane wave method implemented in the WIEN2k code. We employed Perdew–Burke–Ernzerhof generalized gradient and modified Becke–Johnson approximations as exchange–correlation potentials. Our calculated structure parameters are found to be in reasonable agreement with the available literature. It was found that the inclusion of spin–orbit interaction effect shifts the conduction band minima towards the Fermi level and provides band gaps very close to their experimental values. The optical properties such as complex dielectric functions, complex refractive indices, reflectivities, energy loss functions, optical conductivities and absorption coefficients at varied frequencies were investigated in detail. We found that static real part of dielectric functions and refractive index decreases with increase in band gap. Our calculated critical point energies (eV) are consistent with the experimental results.
关键词： optical properties,spin–orbit interaction,electronic properties,structural properties,FP-LAPW
更新于2025-09-19 17:15:36
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Effect of light induced heat treatment on the structural and morphological properties of Linbo3 thin films
摘要： In this research, the spin coating technique has been used to achieve the deposition process of the lithium-niobate. A halogen lamp has used to maintain required heating during the deposition process. A Range of temperatures (60 - 120 °C) was applied on a substrate of a single crystal silicon wafer to maintain high quality deposition process. The deposited films were subsequently annealed to annealing temperature of 500 °C. Films were characterized and analyzed using X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscope (SEM), Raman spectroscopy. The results showed there is a significant impact that the substrate temperature can role over the structural and morphological properties of the prepared films. It also showed that there is a critical value of substrate temperature yields to the best combination of morphological and structural properties. Moreover, the higher values of the refractive index suggest that this material is more suitable for optical waveguides applications.
关键词： Structural properties,Lithium niobate,Nano- and micro-materials,Morphological properties
更新于2025-09-19 17:15:36
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Growth of Atomic Layer Deposited Ruthenium and Its Optical Properties at Short Wavelengths Using Ru(EtCp)2 and Oxygen
摘要： High-density ruthenium (Ru) thin films were deposited using Ru(EtCp)2 (bis(ethylcyclopentadienyl)ruthenium) and oxygen by thermal atomic layer deposition (ALD) and compared to magnetron sputtered (MS) Ru coatings. The ALD Ru film growth and surface roughness show a significant temperature dependence. At temperatures below 200 °C, no deposition was observed on silicon and fused silica substrates. With increasing deposition temperature, the nucleation of Ru starts and leads eventually to fully closed, polycrystalline coatings. The formation of blisters starts at temperatures above 275 °C because of poor adhesion properties, which results in a high surface roughness. The optimum deposition temperature is 250 °C in our tool and leads to rather smooth film surfaces, with roughness values of approximately 3 nm. The ALD Ru thin films have similar morphology compared with MS coatings, e.g., hexagonal polycrystalline structure and high density. Discrepancies of the optical properties can be explained by the higher roughness of ALD films compared to MS coatings. To use ALD Ru for optical applications at short wavelengths (λ = 2–50 nm), further improvement of their film quality is required.
关键词： optical properties,sputtering,structural properties,XUV,ruthenium,soft X-ray,thin film,atomic layer deposition
更新于2025-09-19 17:15:36
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Hybrid gate dielectrics: a comparative study between polyvinyl alcohol/ $$\hbox {SiO}_{2}$$ SiO 2 nanocomposite and pure polyvinyl alcohol thin-film transistors
摘要： Polyvinyl alcohol (PVA) thin films as polymer gate dielectrics, with and without SiO2 nanoparticles were fabricated using spin-coating. Surface roughness and hydrophilicity of PVA and PVA/SiO2 thin films were studied by contact-angle measurements and atomic force microscopy. The dielectric properties were characterized via capacitance and leakage-current measurements on metal–insulator–metal structures. In order to further investigate the application potential of such materials as a replacement for conventional inorganic dielectrics such as SiO2 in organic thin-film transistors, devices were fabricated based on these polymers using α, ω-dihexylquaterthiophene as an active layer. Performance of the devices was realized by electrical measurements and Kelvin probe force microscopy. All transistors showed hole and electron mobilities in the low-voltage range. PVA/SiO2 films showed larger capacitance, less hydrophilicity, rougher surfaces and considerable leakage currents compared with those with neat PVA. Although integrating nanoparticles modified surface electronic properties and showed a shift in surface potential as observed in Kelvin probe force measurements, it appears that non-polymeric and neat polymeric dielectric materials could still be a privilege to nanocomposite polymeric dielectrics for optoelectronic applications.
关键词： ambipolar thin-film transistor,scanning probe microscopy (SPM),surface chemistry,electrical and structural properties,Polymer dielectrics
更新于2025-09-19 17:15:36
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Structural and electrical properties of Sb<sub>x</sub>W<sub>1-x</sub>Se<sub>2</sub> (0, 0.5) ternary alloys
摘要： In present article, we demonstrated for the first time the synthesis and properties of SbXW1-XSe2 (0, 0.5) ternary alloys. The crystals of SbXW1-XSe2 (0, 0.5) ternary alloys were grown by direct vapour transport technique. The XRD results confirm the 2H-hexagonal lattice structure with P63/mmc space group and grown crystals are highly crystallographic c-axis oriented. The screw dislocation mechanism is predominating in the growth process of Sb0.5W0.5Se2 crystals. The results of electrical characterization show n-type semiconducting nature. The Raman spectra exhibit peaks corresponding to out of plane A1g, in-plane E2g and 2LA modes of vibration which is attributing the 2H-polymorph of grown SbXW1-XSe2 (0, 0.5) ternary alloys. The results shows substitution of Sb (+5) on W (+4) lattice site due to similar ionic size. The band gap tailoring from 0.93 to 1.40 eV is achieved, suggesting the effective way to tune the material characteristics for high performance devices.
关键词： structural properties,SbXW1-XSe2 (0,Growth of single crystal,0.5) ternary alloys,electrical transport
更新于2025-09-19 17:15:36
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Structural and electronic properties of liquid, amorphous, and supercooled liquid phases of In <sub/>2</sub> Te <sub/>5</sub> from first-principles
摘要： In2Te5 is a stoichiometric compound in the In–Te system of interest for applications in phase change electronic memories and thermoelectrics. Here, we perform a computational study of the structural, dynamical, and electronic properties of the liquid, supercooled liquid, and amorphous phases of this compound by means of density functional molecular dynamics simulations. Models of the supercooled liquid and amorphous phases have been generated by quenching from the melt. The structure of the liquid phase is characterized by a mixture of defective octahedral and tetrahedral local environments of In atoms, while the amorphous phase displays a mostly tetrahedral local geometry for In atoms with corner and edge sharing tetrahedra similar to those found in the crystalline phases of the In2Te5, InTe, and In2Te3 compounds. Comparison with our previous results on liquid and amorphous In2Te3 and further data on the structural properties of liquid In2Te3 are also discussed. The analysis of the electronic properties highlights the opening of a mobility gap in In2Te5 at about 150 K below the liquidus temperature.
关键词： electronic properties,In2Te5,structural properties,mobility gap,density functional molecular dynamics,phase change materials
更新于2025-09-19 17:13:59
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Synthesis, characterization and thermoelectric performance of Mg2(Si,Sn,Ge) materials using Si-kerf waste from photovoltaic technology
摘要： The recycling acquisition of silicon waste from photovoltaic industry has gained an increasing attention nowadays, since more than 50% of high purity material ends up as kerf during the wafer cutting process. Currently, different Si-based applications are being exploited in terms of using such Si kerf, in order to lower cost and significantly increase environmental impact. Thermoelectric devices can efficiently contribute towards this recycling approach, via the preparation of highly efficient silicides for power generation. In this work, Bi doped Mg2(Si,Sn,Ge) materials were prepared using Si-kerf originated from photovoltaic (PV) cutting wastes. Different Bi concentrations were studied in terms of thermoelectric properties and performance and a high figure-of-merit of 1.1. was achieved at 800K. In addition, a thorough structural and mechanical property characterization, such as morphology, phase identification, hardness and indentation modulus has been conducted. These results, which were evaluated and compared to materials prepared with pure Si (>99.9%), are presented for the first time for Mg2(Si,Sn,Ge) materials.
关键词： magnesium silicides,thermoelectric figure of merit,mechanical/structural properties,multiphase,silicon,recycling
更新于2025-09-19 17:13:59
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Comment on “An effect of novel Nd3+ doping on physical properties of nebulizer spray pyrolysis fabricated ZnS thin films for optoelectronic technology" by A. Jesu Jebathew, M. Karunakaran, K. Deva Arun Kumar, S. Valanarasu, V. Ganesh, Mohd. Shkir, S. AlFaify, A. Kathalingam, in Physica B: Physics of Condensed Matter (2019)
摘要： The present commentary connected with the errors and mistakes made in the structural and morphological properties of Nd3+ doped ZnS thin films by nebulizer spray pyrolysis.
关键词： ZnS thin films,Microstrain,Structural properties,X-ray diffraction
更新于2025-09-19 17:13:59
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Structure, electrical and magnetic properties of Co <sub/>0.8</sub> Zn <sub/>0.2</sub> Fe <sub/>2</sub> O <sub/>4</sub> /(K <sub/>0.47</sub> Na <sub/>0.47</sub> Li <sub/>0.6</sub> ) NbO <sub/>3</sub> bilayered thin films grown by pulsed laser deposition
摘要： Structural, ferroelectric, and magnetic properties of lead-free bilayer composite films with composition (K, Na, Li) NbO3-CoZnFe2O4 (P-S) and CoZnFe2O4-(K, Na, Li) NbO3 (S-P) layers deposited on Pt/Si substrates by a pulsed laser deposition technique have been studied. Structural analysis carried out by X-ray diffraction and Raman scattering confirmed the formation of individual phases of perovskite and spinel without any intermediate/secondary phase. To probe the stoichiometric elemental composition and cationic distribution at the interstitial sites, X-ray photoelectron spectroscopy measurement was carried out, which confirmed the mixed state of Fe-ions valence, while the Zn2+ state was retained. Ferroelectric and ferromagnetic behavior of the bilayered films was observed concurrently depending upon the growth sequence adopted. Magnetic properties of the film with spinel on the top layer exhibited higher saturation magnetization. Dielectric permittivity follows the Maxwell–Wagner polarization caused by thermally agitated carriers. Appreciable ferroelectric properties were achieved in S-P films while the P-S film exhibited a lossy ferroelectric hysteresis loop, which is attributed to a high leakage current value.
关键词： pulsed laser deposition,structural properties,magnetic properties,electrical properties,bilayered thin films
更新于2025-09-16 10:30:52
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Effect of molarities on structural and optical properties of type-II heterostructure CdS/PbS core/shell quantum dot
摘要： The interrelation between particle sizes and crystal structure in core/shell (CS) semiconductor quantum dots has elicited widespread interest. The effects of precursor concentration of chemically synthesized CdS/PbS CS nanoparticles on structural and optical properties have been reported. CdS/PbS CS QDs shows polycrystalline nature with hexagonal phase in X-ray Diffraction (XRD) pattern, which was also confirmed from SEAD pattern. The particle size was found about 15 nm from the HRTEM images, which was also exhibited CS structure of the NPs. EDX and XRD pattern exhibited the formation of pure CdS/PbS CS structure NPs. The strain in the small spherical NPs is dominant; resulting is shifting of XRD peaks towards higher 2θ values and is found to decrease with an increased crystal size of the core. The effect of molarities on the size of the NPs has seen in the absorption spectra and emission spectra with red shifted. The bandgap of the CS NPs varies inversely with the molar concentration of the nanocrystals. The luminescence intensity exhibited increasing trend with the molar concentration of the nanocrystals. The optical properties were found to be in agreement with the structural properties of the CS NPs.
关键词： Molarities effect,Structural properties,Optical properties,CdS/PbS,Core/shell nanoparticles
更新于2025-09-16 10:30:52