Herein, we present the development and characterization of Yttrium oxide (Y2O3) films and Al/Y2O3/n-Si heterojunction diodes at various substrate temperatures using a low-cost facile jet nebulizer spray pyrolysis (JNSP) technique. The X-ray powder diffraction (XRD) pattern proved polycrystalline films of Y2O3 with a cubic structure. Field emission scanning electron microscope (FESEM) images reveal very fine nanograins formation in Y2O3 films at all temperatures. Scanning probe microscopy (SPM) analysis shows very low roughness of all films. The detailed compositional/homogeneity analysis was done via energy dispersive X-ray (EDX)/e-mapping analysis. All the films exhibited a sharp absorption edge at ∼ 280 nm, and the estimated energy gap values were noticed between 4.5 to 4.9 eV. Moreover, the observed photoluminescence (PL) spectrum indicated number of emission peaks in the grown films. From the current – voltage (I-V) characteristic, the calculated ideality factor (n) value was noticed to be drastically reduced from 7.66 to 2.87 on increasing the substrate temperature. Further, the diode ideality factor, series resistance (Rs) and barrier height (ФB) were obtained from Cheung's method. The results revealed that the developed Al/Y2O3/n-Si heterojunction diode is a promising contender for optoelectronic devices.

In this work, we present the synthesis and characterization of molybdenum oxide (MoO3) nanoparticles (NPs). The MoO3 NPs were coated on silicon (Si) wafer to fabricate n-MoO3/p-Si diode by the spin coating method. X-ray diffraction (XRD) profiles clearly show the crystalline nature of all specimens with an orthorhombic crystal system. Stretching and bending vibrations of molybdenum-oxygen were confirmed by the Fourier transform infrared analysis. The maximum absorbance was observed for MoO3 NPs prepared from Nitric acid (HNO3). Nano flakes like morphology were seen by scanning electron microscopy (SEM), and elemental dispersion spectral analysis approved expected Mo and O elements in the final product. Transmission electron microscopy (TEM) analysis of the as-prepared samples indicates a single-phase orthorhombic crystal structure. Electrical conductivity results show that synthesized samples are having semiconducting behavior. It is noted that the p–n junction diode prepared with Hydrochloric acid (HCl) has better rectifying behavior with lower ideal factor (n) values of 2.47 than the other sample.

A three-dimensional hierarchical CuS–CdS@TiO2 multi-heterostructure has been fabricated as a highly promising photoanode for PEC water splitting. The CdS@TiO2 structure was synthesized by a two-step hydrothermal method, therein TiO2 nanorods (TiO2 NRs) were used as the template to grow the CdS branches (CdS BRs). Then the surface of the heterostructure was sequentially coated with a p-type CuS semiconductor via a simple SILAR method. The optimized CuS–CdS@TiO2 photoelectrode exhibits a remarkably high photocurrent density of 12.6 mA cm−2 at 1.23 V vs RHE under standard AM 1.5 light illumination. The enhancement in the PEC performance could attribute to the wide range of solar spectrum absorption in CdS BRs, which can generate more photo charge carriers. Meanwhile, the high conductivity of TiO2 NRs serves as an efficient pathway to transfer photogenerated electrons from the CdS BRs to the FTO substrate. In addition, the p-n junction formed between CuS and CdS@TiO2 heterostructure could improve the separation of electron-hole on the surface of the photoanode. This study demonstrates an efficient pathway to improve the photoelectrochemical performance of TiO2-based photoanodes.

In this work, Mn-doped zinc sulfide (Mn:ZnS) nanoparticles (NPs) have been synthesized as a promising material for photoelectrochemical water splitting (PEC), using the co-precipitation method. PEC properties of Mn-doped zinc sulfide NPs were considered under the correlation between Mn-doping level and their particle size. The highest photocurrent density (8.03 mA cm−2) and largest photoconversion efficiency (0.63%) (at 0.4 V vs. RHE) were reached at 6 mol% Mn. Based on the results of used various materials characterization techniques, including transmission electron microscopy (TEM), X-ray diffraction, photoluminescence spectrum, and absorbance spectrum, it can be assessed that the outstanding PEC characteristics of Mn:ZnS photoanode are attributed to the narrow bandgap of Mn:ZnS nanoparticles and their notably small particle size, which is originated from the Mn-doping. For application, the stability and the effect of various electrolytes were also investigated.

The present paper reports the results of a set of first-principles calculations via Density Functional Theory to characterize the structural, electronic, and magnetic properties of the bulk and (001) surface structures of D022-Mn3Ga. It was found that a Mn-Ga-terminated and another Ga-terminated surfaces are most stable surface reconstructions. The role of C diffusion was evaluated. It has a very localized effect on the magnetic enhancement of these surfaces as it diffuses through them. The magnetic enhancement is also discussed in terms of the surface effect, the magnetoelastic effect, the superexchange interaction, and the Density of States of each atom.

Structural, electronic and magnetic properties of the nitrogenated silicene monolayer have been throughly investigated using first-principles calculations. Pristine silicene single layer adopts a low-buckled structure and presents zero-gap semimetal character with Dirac cone structure at point. N-functionalized silicene monolayers exhibit strong asymmetry of the band structure. Both spin channels exhibit metallic character in a full-nitrogenated layer, while the half-nitrogenation induces the half-metallicity with a perfect spin polarization of 100% at the vicinities of the Fermi level. Our simulations assert that the spin-gapless semiconducting and magnetic semiconducting behaviors may be obtained by applying proper tensile strains to the half-nitrogenated single layer. Significant magnetization of the silicene monolayer is also produced by the N-based functionalization, where total magnetic moments of 2.74 and 1.00 () are obtained in the full- and half-nitrogenated layer, respectively. In addition, the magnetic ground states and their corresponding band structures will be also discussed. Interesting electronic and magnetic properties suggest that the nitrogenation of silicene monolayer may be an effective method to form novel 2D materials for spintronic applications.

This paper reports the synthesis method by sputtered technique for Silicon and Au different thicknesses layers onto glass/FTO substrate, after that the thermal annealing, and then using sol–gel method producing AuNPs@TiO2 plasmonic structure to produce four sample groups: Glass/FTO/AuNPs; glass/FTO/AuNPs/AuNPs@TiO2, glass/FTO/a-Si/AuNPs, and dual combined glass/FTO/a-Si/Au NPs/AuNPs@TiO2 configurations. After thermal annealing, the sputtered Si layer on glass/FTO has amorphous phase (a-Si), sputtered Au layer has crystallized phase in (111) direction and TiO2 has anatase phase. Some optical measurements have investigated such as the transmission, reflection and the absorption measurements were carried out for different sample groups in comparison for choosing the sample group having the highest optical absorption spectrum aiming for application in the modified plasmonic solar cell. The optical absorption of the dual combined glass/FTO/a-Si/AuNPs/AuNPs@TiO2 configuration were significantly enhanced in ultraviolet, visible and near infrared regions with plasmonic resonance peaks shifted depending on Au NPs sizes and a-Si layer thicknesses. This result can be explained by the effects of the dual combined plasmonic structure where the partial /a-Si/Au NPs plasmonic structure has plasmonic resonance around 610 nm with enhanced tail cover to 800 nm, and the partial AuNPs@TiO2 plasmonic structure has plasmonic resonance around 510 nm. The dual combined glass/FTO/a–Si/Au NPs/Au NPs@TiO2 configuration with enhanced absorption spectrum in a wide range that is proposed for applying in the modified plasmonic solar cell for performance enhancement.

Interestingly, significant magnetization of two-dimensional (2D) materials may be induced by doping with nonmetal species. In this work, the structural, electronic, and magnetic properties of pristine and N-, C-, and B-doped graphene-like MgO monolayer have been studied using first-principles calculations. MgO single layer becomes 2D ferromagnetic (FM) semiconductor when substituting one O atom by one N, C, or B atom. Upon increasing doping level, the electronic structure and magnetic properties show a strong dependence on the separation of dopants. The 2N-doped systems exhibit antiferromagnetic (AFM) coupling. The C2 and B2 dimers are formed when replacing two neighboring O atoms, giving place to a non-magnetic semiconductor behavior. However, when these are further apart, significant magnetism is induced due to the long-term effects. Specifically, 2C-doped structure undergoes a FM-AFM-FM-AFM state transition, whereas AFM state is found to be energetically stable for the 2B-doped systems. In all cases, magnetic properties are produced mainly by the dopants, meanwhile the contribution from remaining constituent atoms is quite small. This study suggests an effective approach to tune the electronic and magnetic properties of pristine and doped MgO monolayer by simply controlling the dopant concentration and distance between dopants, which may be helpful for the applications in optoelectronic and spintronic nanodevices.

Great research efforts have been made to introduce high-temperature magnetism in two-dimensional (2D) materials for spintronic applications. In this work, the electronic and magnetic properties of bare and group-VA (N, P, and As) atom doped XC (X = Si and Ge) monolayers have been systematically studied to unravel the doping effects. The pristine monolayers are non-magnetic semiconductors, where the charger transfer from Si and Ge atoms to the C atom is responsible for their wide band gap. The C and X sublattices are identified as preferable doping sites for N and P/As atoms, respectively. Significant magnetism is induced by doping, where the magnetization is stronger in SiC (total magnetic moment of 1 μB) than in GeC (total magnetic moment between 0.69 and 0.98 μB). The magnetic properties of the N-doped SiC monolayer are produced mainly by the first Si neighbor around the doping site, meanwhile P and As atoms induce magnetism in the remaining cases. In addition, the doped systems show diverse electronic structures including metals, half-metals, and magnetic semiconductors, which are regulated mainly by the pz state of the magnetized atoms. The results presented herein may introduce an efficient way to functionalize group-IVA based 2D semiconductor materials for potential spintronic applications by doping with non-magnetic group-VA atoms.

Two extrapolated dynamic string-averaging cutter methods for finding a common fixed point of a finite family of demiclosed cutters in a Hilbert space are developed.  One method converges weakly to a common fixed point of the family. The other converges in norm and is a combination of the method mentioned and the steepest-descent  method. The proof of the strong convergence does not employ any additional cutter related conditions such as approximate shrinking and bounded regularity of their fixed point sets often used in literature. Particular cases of the last method and applications to a convex optimization problem over the intersection of the level sets and the LASSO problem with computational experiments are provided as illustrations.