Semiconductor Characteristics Research Articles

Advanced Neuronal Modulation with Semiconducting Graphitic Carbon Nitride: Insights from In Vitro, In Vivo, and In Silico Studies.

Impaired neuronal functions and cell death within ailments such as neurodegenerative Parkinson's disease pose significant challenges due to their complex pathophysiology and limited treatment options. In this landscape, innovative materials with unique physicochemical properties that ameliorate the debilitated neuronal functions are critically required. Neuronal functions rely on the conduction of nerve impulses, a process that can be effectively targeted using advanced materials that exhibit conducive properties essential for modulating neural activity. For their semiconductor characteristics, combined with well-suited biocompatibility, graphitic carbon nitride (g-C3N4) nanosheets provide promising avenues for such neurotherapeutic applications. Our multidisciplinary study investigates the potential of g-C3N4 nanosheets in promoting neuronal differentiation and network formation across in vitro and in vivo systems. SH-SY5Y cells exposed to g-C3N4 demonstrated enhanced neuronal differentiation and neuritic outgrowth over a chronic 21-days period, accompanied by an increased intracellular Ca2+ influx, pivotal for dopamine biosynthesis, as evidenced by the upregulated expression of vesicular monoamine transporter 2 (VMAT2), aromatic l-amino acid decarboxylase (AADC), and tyrosine hydroxylase (TH) genes. Utilizing transgenic Caenorhabditis elegans model expressing human α-synuclein, we observed the neuroprotective potential of g-C3N4, as evidenced by reduced protein aggregation and improved dopaminergic functions. In the pursuit of exploring the mechanism of g-C3N4-induced neuronal stimulation, the semiconducting nature of g-C3N4 came forth, which was further validated using theoretical (in silico) models. These models demonstrated an increase in the chemical potential of the material upon the application of electrical biases. Studying Ca2+ channel inhibition, we also observed that phenotypic and molecular effects were the outcomes of the stimulation caused due to the presence of g-C3N4 nanosheets. Our findings, supported by experimental and in silico studies, suggest that g-C3N4 nanosheets can effectively modulate neuronal behavior through their semiconducting properties, offering promising avenues for therapeutic interventions in neurodegenerative diseases.

Investigating the Multifunctional Role of Sr2FeMnO6 Double Perovskite in Spintronic and Thermoelectric Properties

Herein, the double‐perovskite Sr2FeMnO6 is investigated using density functional theory to investigate its electronic, magnetic, thermoelectric, and thermodynamic properties. The Sr2FeMnO6 show the ferromagnetic phase stability with the formation energy of about −2.53 eV. Spin‐polarized band structure and density of states (DOS) calculations, performed using the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE‐GGA) and modified Becke–Johnson (GGA + mBJ) methods, confirm a half‐metallic nature. The system exhibits metallic behavior in the spin‐up channel, whereas the low‐spin counterpart demonstrates semiconducting characteristics with a bandgap of about 1.38 eV. A total magnetic moment of 7 μB per formula unit is observed, predominantly originating from Fe and Mn atoms, with induced magnetism in oxygen attributed to Mn‐3d, Fe‐3d, and O‐2p orbital interactions. The thermoelectric behavior of the system is studied by employing the semiclassical Boltzmann theory‐based BoltzTraP code for both spin channels, revealing zT values of 0.98 and 0.94 for spin‐down and spin‐up channels, respectively, with zT decreasing and the power factor increasing with temperature. These findings highlight Sr2FeMnO6 as a promising candidate for spintronics, spin dynamics, and energy‐harvesting applications, offering insights into its multifunctional potential.

Peptide-Perovskite Based Bio-Inspired Materials for Optoelectronics Applications.

The growing demand for environmentally friendly semiconductors that can be tailored and developed easily is compelling researchers and technologists to design inherently bio-compatible, self-assembling nanostructures with tunable semiconducting characteristics. Peptide-based bioinspired materials exhibit a variety of supramolecular morphologies and have the potential to function as organic semiconductors. Such biologically or naturally derived peptides with intrinsic semiconducting characteristics create new opportunities for sustainable biomolecule-based optoelectronics devices. Affably, halide perovskite nanocrystals are emerging as potentially attractive nano-electronic analogs, in this vein creating synergies and probing peptide-perovskite-based bio-electronics are of paramount interest. The physical properties and inherent aromatic short-peptide assemblies that can stabilize, and passivate the defects at surfaces assist in improving the charge transport in halide perovskite devices. This review sheds light on how these peptide-perovskite nano-assemblies can be developed for optical sensing, optoelectronics, and imaging for biomedical and healthcare applications. The charge transfer mechanism in peptides along with as an outlook the electron transfer mechanism between perovskite and short peptide chains, which is paramount to facilitate their entry into molecular electronics is discussed. Future aspects, prevailing challenges, and research directions in the field of perovskite-peptides are also presented.

Influence of Polystyrene Molecular Weight on Semiconductor Crystallization, Morphology, and Mobility

The morphological characteristics of organic semiconductors significantly impact their performance in many applications of organic electronics. A list of challenges such as dendritic crystal formation, thermal cracks, grain boundaries, and mobility variations must be addressed to optimize their efficiency and stability. This paper provides an in-depth overview of how different polymer additives (conjugated, semicrystalline, and amorphous polymers) influence the crystallization, morphology and mobility of some well-studied organic semiconductors. Conjugated polymers enhance molecular alignment and crystallinity, leading to distinct crystalline structures and improved charge transport properties. Semicrystalline polymers offer in-situ crystallization control, which improves film morphology and increases crystallinity and mobility. Amorphous polymers help minimize misalignment and promote parallel orientation of organic crystals, which is critical for effective charge transport. Special attention is given to polystyrene (PS) as a representative additive in this review, which highlights the significant effects of its molecular weight (Mw) on film morphology and charge transport properties. In particular, low-Mw PS (less than 20k) typically results in smaller, more uniform crystals, and enhances both charge transport and interface quality. Medium-Mw PS (20k to 250k) balances film stability and crystallinity, with moderate improvements in both crystal size and mobility. High-Mw PS (greater than 250k) promotes larger crystalline domains, better long-range order, and more pronounced improvement in charge transport, although it may introduce challenges such as increased phase separation and reduced solubility. This comprehensive analysis underscores the decisive role of polymer additives in optimizing the morphology of organic semiconductors and maximizing their charge transport for next-generation organic electronic applications.

Structural, dielectric and magnetic properties of Sb/Cr-doped CaCu3Ti4O12 quadruple perovskite oxides

Driven by the miniaturization of microelectronic devices and their multifunctionalities, the development of new quadruple-perovskite oxides with high dielectric constants and high Curie temperature are highly required. Herein, we report on the structural, dielectric and magnetic properties of Sb/Cr-doped CaCu3Ti4O12(CCTO) quadruple perovskite oxides, CaCu3Ti3.9Sb0.1O12(CCTSO) and CaCu3Ti3CrO12(CCTCO). Structural Rietveld refinements demonstrated that the CCTO, CCTSO, and CCTCO ceramics adopted a cubic crystal structure (Im3¯ space group). They exhibited spherical shapes with nearly uniform particle sizes. XPS spectra clarified Cu3+ions in the CCTSO ceramics, while Cu2+and Cu+ions, and Cr3+ions in the CCTCO ceramics. All the ceramic samples displayed nearly frequency independent dielectric behaviors at low temperatures but a relaxor dielectric behavior at high temperatures. Such relaxor dielectric behavior in the CCTO and CCTSO ceramics was ascribed to the movement of doubly ionized oxygen vacancies but in the CCTCO ceramics to the movement of singly ionized oxygen vacancies. Impedance and modulus spectra reveal the significance contributions of grains and grain boundaries with non-Debye behavior. At room temperature (RT) the dielectric constant (ϵr) and dielectric loss (tanδ) of CCTO ceramics at 1 kHz were 15 922 and 0.126, respectively. An order reduction of tanδwas achieved in the CCTSO ceramics. In the CCTCO ceramics, theϵrand tanδat RT and 1 kHz were 975 and 0.453, respectively. The CCTCO powders exhibited antiferroelectric behavior at 2 K with a saturation magnetization (MS) of 1.42μB/f.u., while theMSfor the CCTSO powders was only 0.027μB/f.u. All ceramic samples exhibited semiconductor characteristics owing to their continuous decreases of resistivity from 2 K to 800 K. Our present work demonstrates an effective route to tuning the dielectric and magnetic properties of CCTO oxides via B-site non-magnetic/magnetic ion-doping.

Probing and manipulating the Mexican hat-shaped valence band of In2Se3

Ferroelectrics based on van der Waals semiconductors represent an emergent class of materials for disruptive technologies ranging from neuromorphic computing to low-power electronics. However, many theoretical predictions of their electronic properties have yet to be confirmed experimentally and exploited. Here, we use nanoscale angle-resolved photoemission electron spectroscopy and optical transmission in high magnetic fields to reveal the electronic band structure of the van der Waals ferroelectric indium selenide (α-In2Se3). This indirect bandgap semiconductor features a weakly dispersed valence band, which is shaped like an inverted Mexican hat. Its form changes following an irreversible structural phase transition of α-In2Se3 into β-In2Se3 via a thermal annealing in ultra-high vacuum. Density functional theory supports the experiments and reveals the critical contribution of spin orbit coupling to the form of the valence band. The measured band structure and its in situ manipulation offer opportunities for precise engineering of ferroelectrics and their functional properties beyond traditional semiconducting systems.

Raman Spectroscopy of Graphene/CNT Layers Deposited on Interdigit Sensors for Application in Gas Detection

Graphene/CNT layers were deposited onto platinum electrodes of an interdigitated sensor using radio-frequency magnetron sputtering. The graphene/CNTs were synthesized in an Argon atmosphere at a pressure of (2 × 10−2–5 × 10−3) mbar, with the substrate maintained at 300 °C either through continuous heating with an electronically controlled heater or by applying a −200 V bias using a direct current power supply throughout the deposition process. The study compares the surface morphology, carbon atom arrangement within the layer volumes, and electrical properties of the films as influenced by the different methods of substrate heating. X-ray diffraction and Raman spectroscopy confirmed the formation of CNTs within the graphene matrix. Additionally, scanning electron microscopy revealed that the carbon nanotubes are aligned and organized into cluster-like structure. The graphene/CNT layers produced at higher pressures present exponential I–V characteristics that ascertain the semiconducting character of the layers and their suitability for applications in gas sensing.

Two-Dimensional Layered Germanium Iodide Perovskite Ferroelectric Semiconductors.

The discovery of ferroelectricity in two-dimensional (2D) semiconductors has opened a new and exciting chapter in next-generation electronics and spintronics due to their lattice-dimensionality-induced unique behaviors and fascinating functionalities brought by spontaneous polarization. The emerging layered halide perovskites with 2D lattices provide a great platform for generating reduced symmetry and low-dimensional ferroelectricity. Herein, inspired by the approach of reduced lattice dimensionality, a series of 2D layered germanium iodide perovskite ferroelectric semiconductors A2CsGe2I7 [where A = PA (propylammonium), BA (butylammonium) and AA (amylammonium)] was firstly developed, which demonstrates remarkable semiconducting features including narrow direct bandgap (~1.8 eV) and high conductivity over 32.23 nS/cm. Emphatically, these layered germanium iodide perovskites manifest large in-plane ferroelectric polarization over ~10.0 μC/cm2, mainly attributed to the large off-centering ion displacement induced by stereo-active lone-pairs of Ge2+ . More specifically, in contrast to three-dimensional ferroelectric CsGeI3, the representative 2D layered BA2CsGe2I7 manifests a superior polarization-sensitive bulk photovoltaic effect with a polarization ratio of 1.68 and high short circuit current density up to 81.25 μA/cm2, superior to those of reported layered halide perovskite ferroelectrics. This work provides an exciting pathway for the development of 2D ferroelectric semiconductorsand sheds light on their further applications in photoelectronic fields.

First-principles predictions of two-dimensional Ce-based ferromagnetic semiconductors: CeF2 and CeFCl monolayers.

Two-dimensional (2D) ferromagnetic (FM) semiconductors hold great promise for the next generation spintronics devices. By performing density functional theory first-principles calculations, both CeF2 and CeFCl monolayers are studied, our calculation results show that CeF2 is a FM semiconductor with sizable magneto-crystalline anisotropy energy (MAE) and high Curie temperature (290 K), but a smaller band gap and thermal instability indicate that it is not applicable at higher temperature. Its isoelectronic analogue, the CeFCl monolayer, is a bipolar FM semiconductor, its dynamics, elastic, and thermal stability are confirmed, our results demonstrate promising applications of the CeFCl monolayer for next-generation spintronic devices owing to its high Curie temperature (200 K), stable semiconducting features, and stability. Under biaxial strain from -5% to 5%, the CeFCl monolayer is a semiconductor with sizable MAE, its Curie temperature can increase to 240 K, the easy magnetization axes for CeFCl monolayer are still along the out-of-plane directions because the couplings between Cef y(3x 2-y 2) and f x(x 2-3y 2) orbitals in the different spin channels contribute most to the MAE according to second-order perturbation theory.

The Problem of Determining the Characteristics of Optical Semiconductors in Plasma Antennas Design and Its Solutions

The Problem of Determining the Characteristics of Optical Semiconductors in Plasma Antennas Design and Its Solutions

Insights into the electronic, magnetic structure, and photocatalytic activity of Y2CuMnO6 double perovskite.

This research aims to develop Y2CuMnO6 double perovskite, using a citrate auto combustion method, to be used as a photocatalyst for the degradation of organic dyes and antibiotics. XRD and Raman characterization revealed the synthesis of pure-phase Y2CuMnO6 double perovskite. The X-ray photoelectron spectroscopy results show the presence of +4 and +2 oxidation states of Mn and Cu ions. Our electronic structure analysis, Mott-Schottky, and UV-vis-NIR analysis suggest strong UV and visible region absorption. Our density functional theory analysis reveals that Y2CuMnO6 exhibits characteristics of a ferromagnetic semiconductor with low effective mass. The Jahn-Teller active Cu2+ ion induces local distortions, contributing to the stabilization of the low-symmetry monoclinic structure (P21/n). The ferromagnetic superexchange mechanism is attributed to the overlap between the empty eg band of Mn4+ and the partially filled eg band orbital of Cu2+. The Y2CuMnO6 double perovskite resulted in degradation efficiencies of 99%, 96%, and 95% of rhodamine B, methylene orange dyes, and tetracycline antibiotics, respectively. This study reveals that the Y2CuMnO6 double perovskite achieved enhanced photocatalytic activity compared to commercial P25 TiO2. It demonstrated the remarkable photocatalytic properties of the Y2CuMnO6 catalyst indicating its significant potential for diverse environmental applications.

Characterization of MgAl2O4 semiconductor prepared by co-precipitation route: application as photocatalyst for tetracycline degradation

Characterization of MgAl2O4 semiconductor prepared by co-precipitation route: application as photocatalyst for tetracycline degradation

Ab initio prediction of a two-dimensional MgO2C6 monolayer with intrinsic semiconducting characteristics: Tunable electronic and optical characteristics through the application of mechanical strain

Ab initio prediction of a two-dimensional MgO2C6 monolayer with intrinsic semiconducting characteristics: Tunable electronic and optical characteristics through the application of mechanical strain

A focus on microporous perovskites: new tricks for an old dog.

Hybrid organic-inorganic perovskites (HOIPs) are widely studied for their potential in optoelectronic devices due to their unique semiconductor features. Porous HOIPs are extremely rare, with (APOSS)[CuCl4]4 being one of the very few examples, featuring 12 Å pores within its lattice. Reed and coworkers (C. W. Dalton, P. M. Gannon, W. Kaminsky and D. A. Reed, Chem. Sci., 2025, DOI: https://doi.org/10.1039/D4SC04378B) have recently shed light on the structure of this interesting material and demonstrated that these pores can incorporate large electroactive molecules such as ferrocene (Fc) and tetracyanoethylene (TCNE). Further, they showed that the ability to incorporate molecules within the pores also enables the synthesis of new crystalline phases and unlocks numerous applications, including gas sensing and photocatalysis, among others.

Distinct Effects of Selective Sn Doping at A or B Sites in BaTiO3

The effects of selectively doping Sn into the A‐site or B‐site of BaTiO3 on its crystal structure and electronic and optical properties are systematically evaluated using first‐principles calculations, leading to several intriguing conclusions. After doping Sn at the A‐site, impurity bands originating from Sn are generated, which alter the direct bandgap to an indirect one and decrease the bandgap value, thereby reducing the electron excitation energy required. Meanwhile, (Ba0.875Sn0.125)TiO3 (A‐site) exhibits p‐type semiconductor characteristics with holes as carriers, which is beneficial for enhancing the conductivity of BaTiO3. The introduction of Sn–O interactions through A‐site Sn doping reduces the density of states of O‐2p near the valence band maximum, enhances the mobility of oxygen ions, and promotes the occurrence of redox reactions. In contrast, when Sn is doped at the B‐site, the bottom of the conduction band shifts toward higher energy levels, leading to a significant increase in the bandgap. In addition, (Ba0.875Sn0.125)TiO3 (A‐site doped) and Ba(Ti0.875Sn0.125)O3 (B‐site doped) exhibit distinct optical behaviors, thereby expanding the optical application range of BaTiO3‐based materials. This study highlights the distinct impacts of Sn doping at the A‐site or the B‐site on the modification of BaTiO3 properties, thereby paving a novel path for designing advanced materials.

Theoretical investigations on the Energy gap, UV- Vis Spectrum and Thermochemical Properties of PVA doped with ZnO andTiO2

Different polymers have attractive multiple properties due to their uses in many fields. The synthesized polymer polyvinly alcohol (PVA) with metal oxide nanoparticles has many applications in different approaches, such as electronics, sensors, optical, optoelectronics, and biomedical fields. The study was carried out within the framework of density functional theory with B3LYP and exchange- correlation energy functionals 6-31G(d, p). Three compounds were PVA and PVA synthesized with zinc oxide (ZnO) and Titanium dioxide (TiO2) nanocomposites. The results proved that using these oxides is a good way to improve the electronic properties of PVA as the energy gap of PVA decreased from 3.8 to 3.4 eV and 3.3 eV PVA/TiO2 and PVA/ZnO, respectively. This demonstrates the good semiconductor character of these compounds with applications related to solar cell manufacturing. The photosensitivity of both PVA/TiO2 and PVA/ZnO samples in FTIR and UV-Vis results indicated that TiO2 and ZnO interacted strongly with PVA. So they can be used in other applications, such as energy storage capacitors. The vibrational mode were then analyzed in terms of force constant and reduced mass, which were relatively constant hydrogen vibrations.

Photocurrent Nanoscopy in the Near Field: A Comparative Study of Different Atomic Force Microscopy Tips in Relation to Their Optical Performance

Photocurrent is a critical observable in a wide range of physical processes across different length scales, serving as a valuable tool for the characterization of semiconductors or two‐dimensional materials. Recently, photocurrent mapping, particularly when combined with magnetothermal transport effects, such as the anomalous Nernst effect (ANE), has been used to image magnetic domains and domain walls. To gain access to photocurrents on the nanoscale, this effect is combined with infrared scattering‐type scanning near‐field optical microscopy, in which strong field enhancement is created at the apex of an atomic force microscopy (AFM) tip, which serves as the confined illumination source creating localized temperature gradients through light absorption in the sample, which can be exploited for ANE detection. Herein, ANE photocurrents generated in a cobalt–iron–boron channel and the optical scattering are compared between various AFM tips, revealing significantly differing behavior for different tips. To gain insight into the origin of these differences, the measurements are further compared to finite element method simulations of tips with varied tip apex radii.

Engineering n-Type and p-Type BiOI Nanosheets: Influence of Mannitol on Semiconductor Behavior and Photocatalytic Activity.

Photocatalytic technology holds significant promise for sustainable development and environmental protection due to its ability to utilize renewable energy sources and degrade pollutants efficiently. In this study, BiOI nanosheets (NSs) were synthesized using a simple water bath method with varying amounts of mannitol and reaction temperatures to investigate their structural, morphological, photoelectronic, and photocatalytic properties. Notably, the introduction of mannitol played a critical role in inducing a transition in BiOI from an n-type to a p-type semiconductor, as evidenced by Mott-Schottky (M-S) and band structure analyses. This transformation enhanced the density of holes (h+) as primary charge carriers and resulted in the most negative conduction band (CB) position (-0.822 V vs. NHE), which facilitated the generation of superoxide radicals (·O2-) and enhanced photocatalytic activity. Among the samples, the BiOI-0.25-60 NSs (synthesized with 0.25 g of mannitol at 60 °C) exhibited the highest performance, characterized by the largest specific surface area (24.46 m2/g), optimal band gap energy (2.28 eV), and efficient photogenerated charge separation. Photocatalytic experiments demonstrated that BiOI-0.25-60 NSs achieved superior methylene blue (MB) degradation efficiency of 96.5% under simulated sunlight, 1.14 times higher than BiOI-0-70 NSs. Additionally, BiOI-0.25-60 NSs effectively degraded tetracycline (TC), 2,4-dichlorophenol (2,4-D), and rhodamine B (Rh B). Key factors such as photocatalyst concentration, MB concentration, and solution pH were analyzed, and the BiOI-0.25-60 NSs demonstrated excellent recyclability, retaining over 94.3% of their activity after three cycles. Scavenger tests further identified ·O2- and h+ as the dominant active species driving the photocatalytic process. In this study, the pivotal role of mannitol in modulating the semiconductor characteristics of BiOI nanomaterials is underscored, particularly in promoting the n-type to p-type transition and enhancing photocatalytic efficiency. These findings provide a valuable strategy for designing high-performance p-type photocatalysts for environmental remediation applications.

A concept for sensor system developments using raw-milk monitoring as a case study

Abstract. In this work, we present a concept for a raw-milk monitoring sensor system aiming at demonstrating a generalized approach for low-cost gas sensor system development in future. These systems are expected to be comparatively less expensive than conventional gas chromatography (GC) systems and can therefore likewise be used by farmers to monitor on-site storage as well as by dairy companies for the inspection of incoming milk and can thus play a significant role in counteracting the waste of milk and its products. This generalizable method is based on three steps: identification of potential milk degradation markers, quantification of these markers, and characterization of metal oxide semiconductor (MOS) sensors for these markers. In the first step, gas chromatography–mass spectrometry (GC-MS) and GC–flame ionization detector (GC-FID)/olfactometry (O) were used to tentatively identify 14 volatile substances in the headspace concentrations above the raw milk. From this, 3-methylbutan-1-ol, hexan-1-ol, pentan-1-ol, acetic acid, and additionally ethanol and ethyl acetate were selected by cross-referencing our results with literature data. In addition, hexanal, 2-methyl-1-propanol, limonene, nonanal, 2-ethylhexan-1-ol, butanoic acid, hexanoic acid, octanoic acid, methyl hexadecanoate, and decanoic acid were identified but not selected as potential markers due to their properties being incompatible with gas mixing apparatus (GMA). In the second step, a proton transfer reaction–MS (PTR-MS) analysis was used to determine the concentration in the headspace, which is in the parts per billion (ppb) range. Investigations of good milk samples and bad milk samples from alpine farms showed that ethanol, 3-methylbutan-1-ol, pentan-1-ol, and hexan-1-ol offered an increasing trend from good to bad milk samples. To enable more precise differentiation, further investigations with a higher sample size are necessary to reveal the feasibility of these markers within the complex matrix of raw milk. In the third step, these selected and literature-confirmed markers were presented to a commercially available sensor, run in a temperature-cycled operation and characterized by a self-developed system. When using ethanol, pentan-1-ol, and hexan-1-ol, a regression model with an accuracy of 42.9 ppb using partial least-squares regression (PLSR) analysis could be established, enabling such sensors to be used in raw-milk monitoring systems in the future.

Sensory properties of dosimetric materials under conditions of parameter fluctuations: Monte Carlo method

The results of ab initio calculations of the thermoluminescent and phospho-rescent characteristics of semiconductors used in dosimetric studies, free from any approximations, are presented. A scaling procedure is proposed to model the sensing capabilities of dosimeters of different types. This makes it possible to establish the scope of various approximations used in practical dosimetry to explain similar experimental data. For the first time, the role of statistical factors determining the range of changes in the energy and kinetic parameters of luminescent processes of actual dosimetric materials in forming their sensory characteristics was investigated. The proposed approach can com-plement the computerized glow curve deconvolution (CGCD) technique, widely used to assess the structure of energy levels and kinetic coefficients of actual dosimetric materials. The capabilities of the new method are implemented in the Lumini calculation package.