Band gap semiconductor

CONTEXT: The 2D AlN/BN planer heterostructure is a promising wide band gap semiconductor, but systematic studies of its bandgap and optical characteristics under applied strain are scarce. Here, the engineering property of 2D AlN/BN comprising bandgap nature transition and optical absorption capability (from unstrained to strained) have been investigated using density functional theory calculations. The formation energy calculations confirm the stability of the simulated nanoheterostructure...

Europium complexes exhibiting red luminescence were prepared by employing β-diketone as main ligand and 1,10-phenanthroline as an additional ligand. Various methods, including 1 H NMR, IR spectroscopy and analysis of optical band gap were employed to examine these complexes. The luminescent photophysical properties were investigated using PL spectroscopy and theoretical calculations were conducted to explore radiative transitions probabilities and Judd-Ofelt (J-O) parameters for transitions of type 5 D0  → 7 F2, 4 ...

In this work, the full-potential linearized augmented plane wave method (FP- LAPW) and the modified Becke-Johnson (mBJ) functional with spin-orbit (SO) coupling are used the obtain the structural, optoelectronic and thermoelectric properties of Tl2 O3 under pressure. The results show that Tl2 O3 , as transparent conducting oxide (TCO), is a direct bandgap semiconductor with a band gap of 1.23 eV. The band gap value and the effective mass of electrons increases by increasing pressure. Density of state spectra reveal that the nature of electrons in Tl-6s state in the bottom of conduction band, like free electrons in s state, is responsible for the conducting behavior of Tl2 O3 ...

Monolayers of transition metal dichalcogenides (TMDCs) are direct-gap semiconductors with strong light-matter interactions featuring tightly bound excitons, while plasmonic crystals (PCs), consisting of metal nanoparticles that act as meta-atoms, exhibit collective plasmon modes and allow one to tailor electric fields on the nanoscale. Recent experiments show that TMDC-PC hybrids can reach the strong-coupling limit between excitons and plasmons, forming new quasiparticles, so-called plexcitons. To describe this coupling theoretically, we develop a self-consistent Maxwell-Bloch theory for TMDC-PC hybrid structures, which allows us to compute the scattered light in the near- and far-fields explicitly and provide guidance for experimental studies...

A novel strategy was employed to create supramolecular metallogels incorporating Tb(iii) and Eu(iii) ions using benzene-1,3,5-tricarboxylic acid (TA) as a gelator in N , N -dimethylformamide (DMF). Rheological analysis demonstrated their mechanical robustness under varying stress levels and angular frequencies. FESEM imaging revealed a flake-like hierarchical network for Tb-TA and a rod-shaped architecture for Eu-TA. EDX analysis confirmed essential chemical constituents within the metallogels. FT-IR, PXRD, Raman spectroscopy, and thermogravimetric analysis assessed their gelation process and material properties, showing semiconducting characteristics, validated by optical band-gap measurements...

Recently, ternary lithium phosphidotetrelates have attracted interest particularly due to their high ionic conductivities, while corresponding sodium and heavier alkali metal compounds have been less investigated. Hence, we report the synthesis and characterization of the novel ternary sodium phosphidogermanate Na3 Ge2 P3 , which is readily accessible via ball milling of the elements and subsequent annealing. According to single crystal X-ray structure determination, Na3 Ge2 P3 crystallizes in the monoclinic space group P 21 / c (no...

A surface photovoltage (SPV) is observed whenever a doped semiconductor with non-negligible band bending is illuminated by light and charge carriers are excited across the band gap. The sign of the SPV depends on the nature of the doping, the amplitude of the SPV increases with the fluence of the light illumination up to a saturation value, which is determined by the doping concentration. We have investigated Si(100) samples with well-characterized doping levels over a wide range of illumination fluences. Surprisingly, the sign of the SPV upon illumination with 532 nm photons reverses for some p-doping concentrations at high fluences...

Biological photo-responsive ion channels play important roles in the important metabolic processes of living beings. To mimic the unique functions of biological prototypes, the transition metal dichalcogenides, owing to their excellent mechanical, electrical, and optical properties, are already used for artificial intelligent channel constructions. However, there remain challenges to building artificial bio-semiconductor nanochannels with finely tuned band gaps for accurately simulating or regulating ion transport...

The study sets out to show the positive impact of sulfur vacancy engineering on the structural, morphological, optical, electrical, and photoelectrochemical (PEC) properties of Sb2 S3 films synthesized using the spin coating technique. The produced films were exposed to γ-irradiation with different doses from 0 to 20 kGy. We have demonstrated the formation of sulfur vacancies and loss of oxygen content in the irradiated samples. XRD measurements revealed that all films exhibit a polycrystalline structure, and the crystallite size increases with the rising radiation dose, reaching the highest value of 87...

The scarcity of superhard materials with magnetism or a narrow band gap, despite their potential applications in various fields, makes it desirable to design such materials. Here, a series of C1+ x N1- x compounds are theoretically designed by replacing different numbers of nitrogen atoms with carbon atoms in the synthesized C1 N1 compound. The results indicate that the compounds C5 N3 and C7 N1 possess both superhardness and antiferromagnetic ordering due to the introduction of low-coordinated carbon atoms...

Modulating the band gap of two-dimensional (2D) transition metal dichalcogenide (TMDC) semiconductors is critical for their application in a wider spectral range. Alloying has been demonstrated as an effective method for regulating the band gap of 2D TMDC semiconductors. The fabrication of large-area 2D TMDC alloy films with centimeter-scale uniformity is fundamental to the application of integrated devices. Herein, we report a liquid-phase precursor one-step chemical vapor deposition (CVD) method for fabricating a Mo x W1- x S2 alloy monolayer with a large size and an adjustable band gap...

Stacking monolayer semiconductors creates moiré patterns, leading to correlated and topological electronic phenomena, but measurements of the electronic structure underpinning these phenomena are scarce. Here, we investigate the properties of the conduction band in moiré heterobilayers of WS2 /WSe2 using submicrometer angle-resolved photoemission spectroscopy with electrostatic gating. We find that at all twist angles the conduction band edge is the K -point valley of the WS2 , with a band gap of 1...

Topological phases in laterally confined low-dimensional nanographenes have emerged as versatile design tools that can imbue otherwise unremarkable materials with exotic band structures ranging from topological semiconductors and quantum dots to intrinsically metallic bands. The periodic boundary conditions that define the topology of a given lattice have thus far prevented the translation of this technology to the quasi-zero-dimensional (0D) domain of small molecular structures. Here, we describe the synthesis of a polycyclic aromatic hydrocarbon (PAH) featuring two localized zero modes (ZMs) formed by the topological junction interface between a trivial and nontrivial phase within a single molecule...

Lacunar spinels, represented by AM4 X8 compounds (A = Ga or Ge; M = V, Mo, Nb, or Ta; X = S or Se), form a unique group of ternary chalcogenide compounds. Among them, GeV4 S8 has garnered significant attention due to its distinctive electrical and magnetic properties. While previous research efforts have primarily focused on studying how this material behaves under cooling conditions, pressure is another factor that determines the state and characteristics of solid matter. In this study, we employed a diamond anvil cell in conjunction with high-energy synchrotron X-ray diffraction, Raman spectroscopy, four-point probes, and theoretical computation to thoroughly investigate this material...

Cation disorder is an established feature of heterovalent ternary nitrides, a promising class of semiconductor materials. A recently synthesized wurtzite-family ternary nitride, ZnTiN2 , shows potential for durable photoelectrochemical applications with a measured optical absorption onset of 2 eV, which is 1.4 eV lower than previously predicted, a large difference attributed to cation disorder. Here, we use first-principles calculations based on density functional theory to establish the role of cation disorder in the electronic and optical properties of ZnTiN2 ...

The optoelectronic, structural, and elastic properties of K2 ScCuCl6 and K2 YCuCl6 double perovskite compounds were thoroughly investigated in this study using density functional theory. It is observed that both compounds exhibit exceptional structural and mechanical stability. The structural stability is assessed using Goldsmith's tolerance factor ( t G ), with values approaching unity indicating a reliable cubic perovskite structure. Phonon stability was ensured by the absence of negative energy formations and only real frequencies in the phonon calculations...

MoS2 -based materials have emerged as photoelectric semiconductors characterized by a narrow band gap, high capacity for absorbing visible light, and reduced H2 adsorption energy comparable to Pt. These attributes render them appealing for application in photocatalytic hydrogen production. Despite these advantages, the widespread adoption of MoS2 -based materials remains hindered by challenges associated with limited exposure to active sites and suboptimal catalytic hydrogen production efficiency. To address these issues, we have designed and synthesized a new class of highly dispersed bimetallic/trimetallic sulfide materials...

As a direct band gap semiconductor, perovskite has the advantages of high carrier mobility, long charge diffusion distance, high defect tolerance and low-cost solution preparation technology. Compared with traditional metal halide perovskites, which regulate energy band and luminescence by changing halogen, perovskite quantum dots (QDs) have a surface effect and quantum confinement effect. Based on the LaMer nucleation growth theory, we have synthesized CsPbBr3 QDs with high dimensional homogeneity by creating an environment rich in Br- ions based on the general thermal injection method...

The electronic structure of carbon nanotube bundles (CNTBs) can be a tough task for the routine first-principle calculation. The difficulty comes from several issues including the atomic structure, the boundary condition, and above all the very large number of atoms that makes the calculation quite cumbersome. In this work, we estimated the band gap of the CNTBs based on the results from single-walled carbon nanotubes (SWCNTs) under different deformations. The effects of squeezing, stretching, and torsion on the bands of SWCNTs were investigated through first-principle calculations, from which the band gaps of bundles were analyzed because the effects of these deformations were qualitatively independent when the distortions were small...

The multi-component glass system has a composition of 10K2 O-10ZnO-55 B2 O3 -(25-x)V2 O5 -xBi2 O3 (x = 4, 5, 7.5, 9, 10 mol%) are synthesized by the melt-quenching method. Using X-ray diffraction examination, the amorphous phase in the material was confirmed. The physical characteristics of the produced compositions are examined using density (D) and molar volume (Vm ). Calculations of physical properties showed that adding Bi2 O3 from 4 to 10 mol% increased the glass density from 2...