Current Applied Physics最新文献

The enhancement of the wettability characteristics in stainless steel holds substantial significance for the application of inhibitor coatings. Investigating a s surface design along with assessing the influences of roughness, surface topography, and chemical heterogeneity on wettability has been a primary focus. In this context, the manipulation of stainless steel surface properties has gained significant attention, specifically for the purpose of fine-tuning wettability. Despite this, uncomplicated surface treatment techniques for stainless steels remain insufficiently established. This study presents a simple etching and oxidation approach for tuning the wettability of stainless steel (STS316L). Through etching and oxidation of STS316L, a superhydrophilic wetting state was achieved (contact angle ∼ 2°). Subsequent application of a monolayer coating led to the reversal of wettability from superhydrophilic to superhydrophobic (contact angle ∼ 168°). Additionally, the proposed methodology for STS316L surface treatment opens up broad expansion possibilities for the applications of superhydrophobic surfaces.

Er³⁺/Nd³⁺ co-doped tellurate glass was prepared by melt quenching method. The relationship between the energy levels of two rare earth ions was studied by absorption spectra and excitation spectra. At 379/407/488 nm excitation, visible light, near-infrared (NIR) emission spectra, and fluorescence attenuation curves were measured. The NIR emission spectrum and fluorescence lifetime show that Er³⁺ can transfer energy to Nd³⁺, thus enhancing the NIR emission of Nd³⁺ in tellurate glass. In the co-doped sample, under excitation of 379/407/488 nm, the NIR emission of Nd³⁺ has a concentration quenching point related to Er³⁺, and the optimal co-doped concentration is 1mol% ErF₃. At 365/451 nm excitation, NIR emission was not enhanced and no energy transfer occurred. In contrast to the energy transfer between conventional Er³⁺-Nd³⁺ co-doped glasses, this paper investigates the effect of matching the higher Er³⁺ energy levels with adjacent Nd³⁺ levels on the energy transfer. The energy transfer process of Er³⁺-Nd³⁺ co-doped glasses is studied in the energy level diagram.

In this article, we introduce our custom-built back-focal plane (BFP) scanning spectroscopy to explore an angle-resolved optical dispersion in two-dimensional (2D) photonic crystal (PhC) constructed with hexagonal lattice of nano-scaled dielectric rods. We fabricated a uniformly large-area photonic crystal measuring 1 cm by 0.5 cm, featuring a polymer-based hexagonal lattice on a gold layer, using capillary force lithography. This precision enables the effective confinement of photonic modes, leading to enhanced optical interactions. We successfully map out the angle-resolved reflectance spectra by directly scanning BFP, revealing the structure's angle dependent optical response and providing insights into its iso-frequency contours. Our approach simplifies the exploration of advanced optical materials, highlighting the role of precise fabrication and measurement techniques in understanding and utilizing the optical properties of structured materials for various technological applications.

In this study, we developed an inductively coupled plasma ion source that can be applied to implanters in semiconductor production. We employed an infrared camera and thermocouples to assess the temperature properties of the ion source operated at temperatures below 500 °C. This reduced temperature is expected to facilitate the adoption of various materials as the ion source. Ion densities of the direct current ion source measured using a double Langmuir probe were found to range from 1.66 × 10¹⁶ to 5.06 × 10¹⁶ m⁻³ within an input power range of 682–895 W. In contrast, the ion densities of a radio-frequency ion source ranged from 7.86 × 10¹⁶–9.58 × 10¹⁶ m⁻³ within an input power range of 700–900 W. This proposed ion source can serve as a next-generation solution because of its low operating temperature and high ion density.

Environmental sensitivity of layered materials necessitates investigating the impact of surrounding materials like hexagonal boron nitride (hBN) on their electrical properties. We investigate the effects of hBN on gate-induced hysteresis in multilayer WSe₂ field-effect transistors (FETs) with four configurations: bare WSe₂, WSe₂ on bottom hBN (b-hBN), WSe₂ under top hBN (t-hBN), and WSe₂ encapsulated with hBN. The presence of b-hBN greatly improves the electrical properties of the two corresponding WSe₂ FETs, leading to a more than tenfold increase in channel currents and a significant reduction in hysteresis. In contrast, the effect of t-hBN is weaker than that of b-hBN. When the environment changes from vacuum to atmospheric conditions, the hysteresis of the two WSe₂ FETs without b-hBN increases substantially, while the change is small for those with b-hBN. Our observations support that pressure-dependent hysteresis originates from gas molecule adsorptions at the WSe₂/SiO₂ interface, not directly on the WSe₂ surface.

Double-perovskite oxides have received interest recently because of their appealing photovoltaic and optoelectronic properties for promising applications. In this paper, we demonstrate the synthesis (solid-state reaction) as well as characterization study of an eco-friendly novel double perovskite CaLiFeWO₆. Preliminary investigation of X-ray diffraction (XRD) data reveals a monoclinic structure. Micro-lattice strain and average size of crystallite are found to be 0.000564 and 86 nm. The distribution of grains and elemental composition of the sintered sample was recorded using scanning electron microscope (SEM) cum energy dispersive X-ray spectroscopy (EDX). Raman scattering spectroscopy is tailored to study the vibrational Raman modes involved in the sample. The optical analysis was investigated by employing UV visible spectroscopy and used to obtain bandgap energy within the range for optoelectronic device applications. To understand the electrical behavior of the synthesized double perovskite, the authors conducted both low and high-frequency dielectric measurements and utilized impedance spectroscopy. The conductivity behavior in the studied material follows Jonscher's power law. Resistance versus temperature data supports the concept of negative temperature coefficient (NTC) thermistors for temperature sensors and temperature control systems. Polarization-electric field supports the possibility of ferroelectric behavior, which opens the door to a wide range of technological advancements and innovations in various fields.

To understand the effects of In₂O₃ on the microstructure, grain size dispersion, density and nonlinear electrical characteristics, ZnO–V₂O₅–Nb₂O₅ varistor ceramics with 0.02, 0.05 and 0.1 mol.% In₂O₃ were fabricated via sintering at 950–975 °C for 1 h. The sintered samples were evaluated by x-ray diffraction, scanning electron microscopy, density measurements and electrical measurements through a voltage source meter. In₂O₃ addition improves relative density to ≥99 % and acts as an efficient grain growth inhibitor, resulting in a narrower grain dispersion and finer ZnO grains due to the formation of In–V–O intergranular phases. The breakdown potential (E_1mA) increases sharply to 7.49 ± 0.3 kV/cm (from 1.66 ± 0.1 kV/cm) as a result of grain size reduction to 2.1 ± 0.1 μm (from 3.89 ± 0.2 μm) with In concentration of 0.1 mol.% (from 0.02 mol.%). Doping of In₂O₃ improves the nonlinear exponent and reduces the leakage current density as a direct consequence of enhanced Schottky barrier height.

In this study, amorphous InAlZnO thin films with varying In:Al:Zn mole ratios of 2:1:2, 4:1:4, and 8:1:8 are deposited using mist chemical vapor deposition (mist-CVD). The X-ray diffraction patterns suggest that these InAlZnO thin films are amorphous. Besides, the O 1s binding energy spectra observed by X-ray photoelectron spectroscopy, photoluminescence, and Tauc plots indicate that oxygen vacancy within the InAlZnO films decreases and bandgap energy of the InAlZnO films increases when the InAlZnO films have higher Al content. The 2:1:2 ratio yields insufficient electrical performance, while the 4:1:4 ratio obtains higher field-effect mobility of 11.42 ± 2.09 cm²V⁻¹s⁻¹, the steepest subthreshold swing of 168.57 ± 27.66 mV/dec, the largest on/off current ratio of (1.76 ± 0.3) × 10⁶, and more stable behavior under negative/positive bias illumination stress. The 8:1:8 ratio reaches the highest field-effect mobility of 27.31 ± 5.13 cm²V⁻¹s⁻¹ while scarifying the stability. This study highlights the impact of Al content on InAlZnO for thin-film transistor applications.

In this study, the elements vanadium (V) and zirconium (Zr) were doped separately as a fourth element to the ternary NiMnIn Heusler magnetic shape memory alloy and the alloys were produced as ingots by arc-melting method. The shape memory properties, microstructures, magnetic and microstructural changes of these new alloys were investigated in detail. The vanadium (V) and zirconium (Zr) elements doped into the alloy caused a decrease in the transformation temperature values of the alloy, but did not cause a significant change in its magnetic properties. The master sample, which has low hysteresis, undergoes a phase transition from the martensite phase to the austenite phase due to an increase in the nucleation of austenite phases at the twinning boundaries. Here, the vanadium and zirconium doping of the alloy caused an increase in the strength and ductility values of the alloy and this caused the formation of the second phase. Due to the increase of this phase formation in the alloy, it can be said that there is a slight decrease in the shape retention of the alloy.

This work presents the influence of O₂ during the cooling stage (CS) after the deposition of the CdTe absorber layer on the photovoltaic parameters of CdTe/PEDOT:PSS hybrid solar cells. The CdTe samples were processed by closed space sublimation (CSS) at a constant deposition pressure of 100 mTorr under 50 %Ar + 50 %O₂ atmosphere. After CdTe deposition, the CSS system remained at a constant pressure of 50 mTorr for 10 min of the CS under different Ar + O₂ atmospheres and in vacuum, in order to study the influence of the cooling atmosphere on the optical, morphological and structural properties of CdTe and on the photovoltaic parameters of the CdTe/PEDOT:PSS hybrid solar cells. In addition, different cooling times (from 10 to 90 min) were studied in an O₂-only atmosphere, when the cooling temperature decreased from 500 to 300 °C inside the CSS system, at the same pressure. SEM micrographs showed changes in the surface morphology of CdTe when cooled in O₂ atmosphere; while, EDS showed a slight modification in Te/Cd ratio for some samples with O₂ during CS. Carrying out a cooling process in O₂ atmosphere for 10 min allows improving the photovoltaic parameters J_sc, V_oc, FF, and η of the obtained hybrid solar cells. For cooling times longer than 30 min, the values of V_oc and J_sc started to decrease. The solar cells with cooling times of 10 and 30 min in an O₂ atmosphere show in the J vs. V curves an increase mainly in the V_oc, FF and shunt resistances associated with the mitigation of defects at the interfaces and inside the materials, which may be due to a passivation of the absorber material. Solar cells with an O₂ cooling atmosphere also show an essential increase in the EQE response.