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The structural and elastic properties of InSb1-xBix alloys
摘要： Based on density functional theory, the structural and elastic properties of InSb1-xBix alloys have been studied using first principle calculations. The generalized gradient approximation in the presence of spin-orbit coupling is utilized to perform the calculations presented in this paper. The calculated lattice constants of InSb1-xBix alloys are in good agreement with the available experimental data. The mechanical stability of these alloys is demonstrated using elastic constants. The ductility and brittleness of these alloys are investigated using both Poisson’s ratio and Pugh’s ratio. Moreover, the anisotropy of InSb1-xBix alloys is studied using the universal index and the 3D representation of Young's modulus. According to the obtained values of Poisson’s ratio, the InSb0.5Bi0.5 and InBi alloys are auxetic materials.
关键词： InSb1-xBix alloys,structural properties,Density functional theory,elastic properties
更新于2025-09-04 15:30:14
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Effects of Al2O3 buffer layer and annealing on the structural and optoelectronic properties of AZO films
摘要： Transparent conductive aluminum-doped ZnO (AZO) films are deposited on glass substrates using radio frequency (rf) magnetron sputtering, with an AZO ceramic target (Al2O3 content is ~ 3 wt%). Before the AZO films is coated, the hydrophilicity of the surface of the glass substrate is increased by oxygen plasma etching. The grey Taguchi method is used to determine the effect of the deposition parameters on the structural and optoelectronic properties of AZO films. In the confirmation runs, using the grey Taguchi method, an improvement of 46.3% in electrical resistivity and of 1.74% in transmittance is observed. The effect of an Al2O3 buffer layer is also determined. When the thickness of the Al2O3 buffer is increased (from 50 nm to 150 nm), the intensity of the (0 0 2) peak for the AZO films increases and the peaks become sharper, the resistivity of the AZO films is decreased and the transmittance is slightly reduced. Annealing at 500 °C in a vacuum (2.0 Pa) for a period of 30 min, increases the performance of the AZO/Al2O3/glass to better than that for AZO/glass samples. Using a Rockwell-C hardness tester, the AZO/Al2O3 (50 nm)/glass film are classified as HF1, which represents good adhesive mechanical strength. The crystallinity of AZO/Al2O3 (50 nm)/glass samples that are annealed at 500 °C for 30 min is improved, the electrical resistivity is 9.70 × 10?4 ? cm and the optical transmittance in the visible region is approximately 85%. The figure of merit shows that the bi-layer films have better optoelectronic performance.
关键词： optoelectronic properties,AZO films,Al2O3 buffer layer,structural properties,annealing
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) GREEN DESIGN AND MANUFACTURE: ADVANCED AND EMERGING APPLICATIONS: Proceedings of the 4th International Conference on Green Design and Manufacture 2018 - Ho Chi Minh, Vietnam (29–30 April 2018)] - Study of geometrical and electronic structure of lanthanum doped PbTiO3 and PbZrTiO3: First principles calculation
摘要： Structural and electronic properties of tetragonal (space group P4mm) of PbLaTiO3 and PLaZT are investigated using pseudopotential plane wave method within the local density approximation (LDA) and generalized gradient approximation (GGA) with virtual crystal approximation (VCA) calculation. The calculated structural parameters for PbLaTiO3 and PLZT are consistent with the obtainable experimental data (XRD) and previous calculations. The band structures show that PbLaTiO3 and PLaZT have small band gap about 1.600 eV and 2.263 eV compared with pure PbTiO3 and PZT respectively. The density of states show that the effect of B-site cation (Ti 3d and Zr 4d) was the important part of covalency for O 2p and La 5p in PbLaTiO3 and PLaZT. Our calculated results can be seen as a prediction for future investigations.
关键词： structural properties,lanthanum doped PbTiO3,electronic properties,PbZrTiO3,first principles calculation
更新于2025-09-04 15:30:14
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Structural, Linear and Third Order Nonlinear Optical Properties of Sol-Gel Grown Ag-CdS Nanocrystalline Thin Films
摘要： Pure and Ag doped CdS nanocrystalline ?lms with different Ag doping concentrations were successfully grown on glass substrates by a sol-gel spin coating method. Ag doping was performed using silver acetate aqueous solution with 0.01, 0.02 and 0.03 M concentrations via ion exchange. The in?uences of Ag doping on structural, vibrational, morphological, linear and third order nonlinear optical properties of CdS nanocrystalline ?lms were studied. The x-ray diffraction patterns of the ?lms exhibited a broad peak centered at an angle 2h = 26.5(cid:2) along the (111) plane, which con?rms the cubic structure and formation of nanocrystalline ?lms. Raman spectra of ?lms demonstrate a shift in longitudinal optical phonon vibrations as compared to the bulk counterpart. Pure CdS ?lm shows high transmittance (83%) in the visible and near infrared (NIR) regions. With Ag doping, a signi?cant red shift in the band edge and reduction in the transmittance of the ?lms in visible and NIR regions were observed. However, the ?lms doped with Ag showed appreciable transmittance in visible region for window layer applications. A signi?cant effect on optical parameters such as absorption index, refractive index, and optical dielectric constant was observed after Ag doping. The nonlinear optical properties of ?lms were enhanced with incorporation of Ag atoms into the CdS binary system. The values of nonlinear optical susceptibility v(3) and refractive index n2 were found to increase with increasing Ag concentration and were estimated to be in the range of 2.92 9 10(cid:2)10 (cid:2) 1910(cid:2)7 esu and 1.00 9 10(cid:2)9 2.00 9 10(cid:2)7 esu, respectively. These values suggest that these ?lms can be potential candidates for nonlinear optical device applications.
关键词： structural properties,optical properties,surface morphology,Ag-CdS,Raman spectroscopy
更新于2025-09-04 15:30:14
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Structural and optical properties of sulfur passivated epitaxial step-graded GaAs <sub/>1-y</sub> Sb <sub/>y</sub> materials
摘要： The impact of bulk and surface defect states on the vibrational and optical properties of step-graded epitaxial GaAs1-ySby (0 ≤ y ≤ 1) materials with and without chemical surface treatment by (NH4)2S was investigated. Tunable antimony (Sb) composition GaAs1-ySby epitaxial layers, grown by solid source molecular beam epitaxy (MBE), were realized on GaAs and Si substrates by varying key growth parameters (e.g., Sb/Ga ?ux ratio, growth temperature). Raman and photoluminescence (PL) spectroscopic analysis of (NH4)2S-treated GaAs1-ySby epitaxial layers revealed composition-independent Raman spectral widths and enhanced PL intensity (1.3×) following (NH4)2S surface treatment, indicating bulk defect-minimal epitaxy and a reduction in the surface recombination velocity corresponding to reduced surface defect sites, respectively. Moreover, quanti?cation of the luminescence recombination mechanisms across a range of measurement temperatures and excitation intensities (i.e., varying laser power) indicate the presence of free-electron to neutral acceptor pair or Sb-defect-related recombination pathways, with detectable bulk defect recombination discernible only in binary GaSb PL spectra. In addition, PL analysis of the short- and long-term thermodynamic stability of sulfur-treated GaAs1-ySby/Al2O3 heterointerfaces revealed an absence of quanti?able atomic interdiffusion or native oxide formation. Leveraging the combined Raman and PL analysis herein, the quality of the heteroepitaxial step-graded epitaxial GaAs1-ySby materials can be optimized for optical devices.
关键词： molecular beam epitaxy,optical properties,structural properties,sulfur passivation,Raman spectroscopy,surface treatment,photoluminescence spectroscopy,GaAs1-ySby
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Physical investigations of nano and micro lithium-niobate deposited by spray pyrolysis technique
摘要： In this paper, lithium-niobate thin films were deposited using spray pyrolysis method. Further investigations of the physical properties of prepared samples were also studied. The spray pyrolysis deposition method was performed over a quartz substrate employing new raw materials as precursor compounds. During the deposition process, a range of annealing temperatures were set to maintain a physical changes in the prepared samples properties. Further, the structural properties were also characterized using field emission scanning electron microscope (FE-SEM), AFM, and film thickness.
关键词： structural properties,Spray pyrolysis,Lithium-Niobate,morphological properties
更新于2025-09-04 15:30:14
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Influence of rare earth material (Sm3+) doping on the properties of electrodeposited Cu2O films for optoelectronics
摘要： Herein, we report samarium (Sm) dopant concentration effect on Cu2O films characteristics prepared by electrodeposition method. XRD patterns of the films indicated that pristine and Sm:Cu2O films have polycrystalline cubic structure with (111) preferred orientation. It was seen from the SEM photographs pinhole free dense triangle shaped grains for undoped Cu2O thin films and the grain size was decreased as concentration of samarium was increased. Raman spectroscopy showed peaks at 108, 146, 217, 413 and 637 cm?1 which conformed the Cu2O phase formation and intensity of the peaks was decreased with a increase in dopant concentration. UV–Vis spectra exhibited that the absorption value of Cu2O films is increased gradually with reduction in band gap value for the increase of samarium content. Photoluminescence (PL) spectra revealed that all films display a visible light emissions and its intensity was reduced due to increase in doping concentration. Photosensitivity observation study indicated that the photocurrent of deposited Cu2O films was increased along with the increase in dopant material concentration.
关键词： Electrodeposition,Cu2O films,Optoelectronics,Structural properties,Samarium doping,Optical properties,Photosensitivity
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Effects of Ag dopant and ultraviolet irradiation on structural properties of zinc oxide nanostructures
摘要： ZnO nanorods are promising UV light driven photocatalyst for the degradation of organic dyes. In this work, the effects of Ag dopant (0.02 to 0.1 mol%) and ultraviolet irradiation (0 to 6 min) on structural, optical and photocatalytic properties of zinc oxide nanorods were investigate. The Ag incorporation ZnO nanoraod have been grown on glass substrate by chemical solution deposition method. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis absorption spectroscopy (UV–vis). The XRD spectra of the Ag incorporation ZnO (Ag-ZnO) films indicate that Ag was incorporated in the wurtzite hexagonal crystal structure of ZnO and the crystallinity were enhanced with increasing of Ag amount as well as ultraviolet irradiation time. SEM micrographs of pure ZnO films revealed the uniform distribution of rod-like nanostructure of size of about 30-40 nm. Increasing Ag amount as well as irradiation time stimulated the optical properties of ZnO nanostructures. The photocatalytic activity of these nanostructures was evaluated by analysing UV irradiation degradation of methyl orange (MO) dye and it was observed that Ag-ZnO show significantly enhanced photocatalytic activity for degradation of MO, as compared to ZnO nanorods.
关键词： structural properties,ZnO nanorods,ultraviolet irradiation,Ag dopant,photocatalytic activity
更新于2025-09-04 15:30:14
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Growth and Structural Properties of Graphene Oxide Thin Film with Spray Pyrolysis Technique
摘要： The spray pyrolysis technique (SPT) is one of the most useful and simple methods to grow graphene oxide (GO) thin film. Good-quality GO thin films were fabricated by spray coating with GO powder (prepared by the modified Hummers method) on glass substrates. Raman spectroscopy, Field Emission Scanning Electron Microscope (FESEM), X-ray diffraction (XRD) analysis, and UV–visible spectroscopy were done to observe the presence of functional groups in the growth thin films and to determine the structure of GO. From the result of XRD test, the GO demonstrates peak at 10.58°(2θ), while the Raman spectroscopy reveals the presence of two prominent peaks, known as D and G bands, as well as 2D band. The ID/IG ratio for spray-deposited GO film was calculated with the value of 0.84. FESEM images showed that the glass substrates were completely covered by GO at different magnifications with a sheet-like structure. The optical absorption of graphene oxide was also observed at a wavelength rang of 275-350 nm.
关键词： Graphene Oxide,Thin Film,Spray Pyrolysis Technique,Structural Properties
更新于2025-09-04 15:30:14
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Metamorphic InAs(Sb)/InGaAs/InAlAs nanoheterostructures grown on GaAs for efficient mid-IR emitters
摘要： High-efficiency semiconductor lasers and light-emitting diodes operating in the 3–5 μm mid-infrared (mid-IR) spectral range are currently of great demand for a wide variety of applications, in particular, gas sensing, noninvasive medical tests, IR spectroscopy etc. III-V compounds with a lattice constant of about 6.1 ? are traditionally used for this spectral range. The attractive idea to fabricate such emitters on GaAs substrates by using In(Ga,Al)As compounds is restricted by either the minimum operating wavelength of ～8 μm in case of pseudomorphic AlGaAs-based quantum cascade lasers or requires utilization of thick metamorphic InxAl1-xAs buffer layers (MBLs) playing a key role in reducing the density of threading dislocations (TDs) in an active region, which otherwise result in a strong decay of the quantum efficiency of such mid-IR emitters. In this review we present the results of careful investigations of employing the convex-graded InxAl1-xAs MBLs for fabrication by molecular beam epitaxy on GaAs (001) substrates of In(Ga,Al)As heterostructures with a combined type-II/type-I InSb/InAs/InGaAs quantum well (QW) for efficient mid-IR emitters (3–3.6 μm). The issues of strain relaxation, elastic stress balance, efficiency of radiative and non-radiative recombination at T = 10–300 K are discussed in relation to molecular beam epitaxy (MBE) growth conditions and designs of the structures. A wide complex of techniques including in-situ reflection high-energy electron diffraction, atomic force microscopy (AFM), scanning and transmission electron microscopies, X-ray diffractometry, reciprocal space mapping, selective area electron diffraction, as well as photoluminescence (PL) and Fourier-transformed infrared spectroscopy was used to study in detail structural and optical properties of the metamorphic QW structures. Optimization of the growth conditions (the substrate temperature, the As4/III ratio) and elastic strain profiles governed by variation of an inverse step in the In content profile between the MBL and the InAlAs virtual substrate results in decrease in the TD density (down to 3 × 107 cm?2), increase of the thickness of the low-TD-density near-surface MBL region to 250–300 nm, the extremely low surface roughness with the RMS value of 1.6–2.4 nm, measured by AFM, as well as rather high 3.5 μm-PL intensity at temperatures up to 300 K in such structures. The obtained results indicate that the metamorphic InSb/In(Ga,Al)As QW heterostructures of proper design, grown under the optimum MBE conditions, are very promising for fabricating the efficient mid-IR emitters on a GaAs platform.
关键词： Buffer layer,Non-radiative recombination,Mid-infrared emitters,Photoluminescence,Metamorphic heterostructures,InSb,InAs,Structural properties,Molecular beam epitaxy,Nanostructures,In(Ga,Al)As ternary alloys,Threading dislocations,Quantum well
更新于2025-09-04 15:30:14