Donor Concentration Research Articles

Shifting official development assistance during COVID-19: earmarking, donor concentration and loans

ContextIn contrast to bilateral aid, aid disbursed from multilateral institutions increased significantly at the onset of the COVID-19 pandemic. Yet, at a time when a coherent and effective multilateral response...

Silver doping effect on the electrochromic performance of the WO3 thin films produced by thermal evaporation in vacuum

Ag doped WO3 thin films are successfully fabricated by thermal evaporation method in vacuum as precursor, and then annealed at 450 °C in nitrogen gases atmosphere. Cyclic voltammetry, repeating chronoamperometry, chronocolumetry and optical transmittance are recorded in 1 M LiClO4/propylene carbonate electrolyte. The color of the WO3 thin films changes from transparent to the blue under the applied potential of -1.8 and +1.9 V. XRD studies show that all the films have a polycrystalline structure of WO3. The molecular formation is also confirmed by Raman and X-Ray photoelectron spectroscopy (XPS). The EDS elemental mappings clearly confirm the homogeneous distribution of Ag, W and O elements into the WO3 network. From the optical studies, indirect band gap energy of the WO3 decreases as Ag doping level increases. The best coloration and bleaching times (2.33 and 1.25 s) are obtained for the Ag(2%):WO3 thin films, compared to the pure WO3 (3.79 and 1.96 s). The produced WO3 films exhibit high reversibility (39.6/69.1%), high coloration efficiency values (26.3/141.2 cm2/C), and good cycling stability. From the EIS measurements, the charge-transfer resistance is Ag(2%):WO3 < the pure WO3 < Ag(5%):WO3 < Ag(8%):WO3, which means that Ag(2%):WO3 has the biggest electrochemically active surface area. Electronic energy levels of the pure WO3 and the Ag:WO3 thin films are also given. From the Mott-Schottky studies, it is determined that the donor concentration of the materials is of the order of 1014-1015 cm−3. In the literature, there are very limited studies related to electrochromic thin films by thermal evaporation in vacuum. In this sense, the reported results in this study are promising for the electrochromic applications.

Impact of methanogenesis inhibitors on a mixed dechlorinating community in TCE contaminated groundwater

Trichloroethene (TCE) is a chlorinated solvent that can adversely affect human health. TCE-contaminated groundwater bioremediation relies on the presence of an active and diverse reductively dechlorinating microbial community. This process requires the presence of reduced conditions, which are also favorable to methanogens. Methanogens and dechlorinating bacteria can both use hydrogen for metabolism thus competition can arise. Previous studies have indicated that methanogens might also be beneficial for the dechlorinating microbial community since they can provide enzymes, cofactors and vitamins necessary for the metabolism. In this study, the methanogenesis inhibitors garlic oil (GO) and 2-chloroethanesulfonate (CES) were assessed for their effect on reductive dechlorination and methanogenesis in TCE contaminated groundwater. GO has been used in the field as a methanogenesis inhibitor but limited information is available on its effects on the microbial community. The results from this study indicated that GO did not impact the activity of the microbial community, while CES partially inhibited methanogenesis. At the assessed electron donor concentration (5 mM) neither of the compounds affected TCE dechlorination in the reactor microcosms. This information can be beneficial for decision-makers, when designing a TCE-bioremediation plan to assess the need for amendments to enhance long-term TCE dechlorination activity at the site.

Syn vs. Anti? What Controls Addition Stereochemistry in Chlorolactonization.

The stereochemistry of the uncatalyzed chlorolactonization of 4-phenylpent-4-enoic acid at room temperature was examined to probe the reaction's intrinsic diastereoselectivities as a function of chlorenium ion donor, solvent polarity, and reactant concentration ranges. Kinetic studies using Variable Time Normalization Analysis (VTNA) revealed differing reaction orders for the syn and anti alkene addition processes. Aided and illustrated by quantum chemical modeling, this detailed mechanistic analysis of the substrate's intrinsic chlorolactonization reactions points to concerted AdE3-type paths for both syn and anti additions. By illuminating the factors selecting for syn- vs anti-addition paths, the results provide key reference points for future studies of stereocontrol in halofunctionalization reactions.

Potentiostatic electrodeposition of copper, indium, and cadmium sulfides for CO2 electroreduction: A path toward sustainable hydrogen generation

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In2S3, and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In2S3, and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In2S3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In2S3, and CdS were found to have donor and acceptor concentrations (ND) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications.

Epitaxy of &gt;7 μm Thick GaN Drift Layers on 150 mm Si(111) Substrates Realizing Vertical PN Diodes with 1200 V Breakdown Voltage

Metal‐organic chemical vapor deposition growth of vertical GaN PN structures on 6″ Si(111) substrates enabling a 1200 V breakdown voltage is demonstrated. Thanks to an optimized buffer structure utilizing island growth in an AlN/Al0.1Ga0.9N superlattice, the threading dislocation density is drastically reduced, and sufficient compressive stress is incorporated in active GaN layers to compensate for the thermal mismatch. Crack‐free PN structures with drift layer thicknesses up to 7.4 μm are realized with a threading dislocation density of ≈5 × 108 cm−2 and an absolute wafer bow &lt;50 μm. Quasi‐vertical PN diodes reveal a linear increase in the breakdown voltage with the drift layer thickness with an average breakdown field of ≈1.6 MV cm−1. Additionally, the leakage current is shown to decrease monotonically as the drift layer thickness increases. For a 7.4 μm thick drift layer with a net ionized donor concentration of 0.9 × 1016 cm−3, a high breakdown voltage of 1200 V, a low specific on‐resistance of 0.4 mΩ cm−2, and a low leakage current of 10−4 A cm−2 (at a reverse bias of 650 V) are obtained. These results demonstrate the great potential of cost‐effective vertical GaN‐on‐Si power devices operating in the kilovolt range.

Overload of dissolved organic matter (DOM) in riparian infiltration zone increasing the pollution risk of naphthalene, insight from the competitive inhibition of naphthalene biodegradation by DOM.

Riparian infiltration zones are crucial for maintaining water quality by reducing the aqueous concentrations of polycyclic aromatic hydrocarbons (PAHs) through adsorption and biodegradation within the aquatic ecosystem. Dissolved organic matter (DOM) are ubiquitous in riparian infiltration zones where they extensively engage in the adsorption and biodegradation of PAHs, thereby influencing PAHs natural attenuation potential within riparian infiltration zones. Few studies have explored the natural attenuation mechanisms of PAHs influenced by DOM in riparian infiltration zones. In this study, the natural attenuation mechanisms of naphthalene (a typical PAHs component), under the influence of DOM, were explored, based on a case riverside source area. Analysis of microbial community structures, and the electron acceptor (e.g., Fe(III), DO/NO3-, SO42-)/electron donor (naphthalene and DOM) concentration changes within the riparian infiltration zone revealed a competitive inhibition relationship between DOM and naphthalene during microbial metabolism. Biodegradation experiments showed that when the concentration of DOM is higher than 4.0 mg·L-1, it inhibits the biodegradation of naphthalene. DOM competitively inhibits the biodegradation of naphthalene through the following mechanisms: (i) triggering microbial antioxidative defense mechanisms, diminishing the available resources for microbial participation in naphthalene degradation; (ii) altering microbial community structure; (iii) modulating microbial EPS composition, reducing the efficiency of microorganisms in utilizing carbon sources; and (iv) inhibiting the expression levels of downstream genes involved in naphthalene degradation. The competitive inhibition constants of DOM with concentrations of 1.0, 2.0, 4.0, 8.0, and 16.0 mg·L-1 on naphthalene biodegradation are -2.0 × 10-3, -5.0 × 10-3,1.0 × 10-3, 4.0 × 10-4, and 1.0 × 10-4, respectively. These findings enhance understanding of PAHs attenuation in riparian infiltration zone, providing a basis for assessing and managing PAHs pollution risks during riparian extraction.

Carrier scattering and temperature characteristics of mobility and resistivity of Fe-doped GaN

Abstract The electron mobility and dark resistivity of Fe-doped semi-insulating GaN (GaN:Fe) are calculated over the temperature range from 10 K to 500 K by considering the impurities compensation mechanism and majority carrier scattering. The temperature characteristic curve of the mobility exhibits unimodality and the curve of resistivity decreases monotonically with rising temperature. The carrier scatterings induced by ionized impurities, acoustic deformation potential, piezoelectric, and polar optical phonons are analyzed. It is found that the mobility is determined by ionized impurity scattering, piezoelectric scattering, and polar optical phonon scattering in different temperature ranges, and the contribution of acoustic deformation potential scattering is negligible over the entire temperature range. Furthermore, the effects of concentrations of shallow donors and deep acceptors on the temperature characteristic curves of mobility and resistivity, the peak mobility and its corresponding temperature (peak temperature), and the mobility and resistivity at room temperature are discussed. Our simulation shows the calculation results agree very well with the reported experimental and theoretical results when the Fe-related level is selected as 0.58 eV below the conduction band edge. Understanding of thermal properties of dark resistivity and mobility can be useful for optimizing GaN:Fe-based electronic and photonic devices performance in different temperature regimes.

Cathodic shift in flatband potential of hematite based photoelectrodes: Evaluating and correlating the redshift to solar driven photocatalysis

As a promising metal oxide semi-conductor, hematite (α-Fe2O3) has interesting optical properties to be regarded as photoactive material. In this study, we evaluated the cathodic shift in onset potential (Eonset) and the negative shift in flat band potential (Efb). It was observed that the Eonset value of −0.457 V for α-Fe2O3 based electrode shifted to −0.638 V for the ternary nanocomposite (PNFC) [Pani/Ni-α-Fe2O3/CNT] based electrode. The flat band potential for α-Fe2O3 in 1 M NaOH is at −0.49 V which shifts to −0.68 V for the ternary nanocomposite (PNFC). This photoelectrochemical enhancement appears due to electron-hole pair separation. Therefore, it apparently increases the photocurrent trace for PNFC at −0.60 V to 7.04 mA cm-2, compared to the photocurrent of 4.52 mA cm-2 observed for pristine α-Fe2O3. According to the Mott-Schottky plot, the donor concentration (Nd) for the α-Fe2O3 is 4.83 × 109 cm-3, whereas for the ternary nanocomposite (PNFC) is 7.68 × 109 cm-3, respectively. As evident, the Nd value increase for the ternary nanocomposite PNFC points to the proximity of the Fermi (Ef) level below the CB edge when Ni doped α-Fe2O3 comes in contact with polyaniline (Pani). Indeed, the ternary nanocomposite PNFC with lower Eg value (1.32 eV) and higher photocurrent (7.04 mA cm-2) show higher photo-activity with percent degradation of 98.42 % for photocatalytic degradation of Sunset Yellow under visible light irradiation. The aforementioned correlations of the energetic levels of band edges with the shifting of Efb to more negative potentials provide insight into the high photo-activity observed.

Study of electrical properties of fullerene based all-small-molecule low donor organic devices with and without cathode buffer layers for photovoltaic application

This article examines electrical properties of fullerene (C70) based all-small-molecule organic photovoltaics with low donor concentration. Enhancements in the properties of devices are observed with the incorporation of lithium fluoride (LiF) and molybdenum trioxide (MoO3) as cathode buffer layers (CBLs). Samples are characterized using field emission-scanning electron microscopy (FESEM), optical absorption spectra, current-voltage (I-V) characteristics in dark and under illumination, and capacitance-frequency (C-ω) measurements. Device with single CBL (LiF) exhibits reduced photoabsorption leading to less saturation photocurrent density (Jsat) and lower maximum exciton generation rate (Gmax), due to non-uniform deposition of LiF in device. In contrast, device having two CBLs (LiF & MoO3) has enhanced the photoabsorption exhibiting high Jsat and Gmax attributed to uniform deposition of MoO3. Moreover, dielectric properties and AC conductivity of devices are also measured confirming the results and these are found to be dependent on the frequency and voltage.

Nature of electrically detected magnetic resonance in highly nitrogen-doped 6H -SiC single crystals

This work focuses on unraveling electron paramagnetic resonance (EPR) and electrically detected magnetic resonance (EDMR) properties of n-type 6H silicon carbide (SiC) single crystals with high concentrations of uncompensated nitrogen (N) donors, which is essential for fundamental understanding of spin-related phenomena, developing spin-based devices, optimizing materials and devices, and advancing research in quantum information and spintronics. Utilizing low-temperature multifrequency EPR spectroscopy (9.4–395.12 GHz), we identified two intense signals labeled as S line and S1 line in the 6H-SiC crystals with ND–NA≈8×1018 and 4×1019cm−3. In addition, in 6H-SiC crystals with ND–NA≈8×1018cm−3, a low-intensity triplet from N donors substituting the quasicubic “k2” nonequivalent position (Nk2) was observed. The S line [g⊥=2.0029(2),g∥=2.0038(2)] was assigned to the exchange interaction of conduction electrons and Nk2, while the S1 line [g⊥=2.0030(2),g∥=2.0040(2)] is caused by the exchange spin coupling of localized N donors at the “k1” and “k2” positions. The S1 line was observed in high-frequency EDMR spectra of 6H-SiC with ND–NA≈8×1018cm−3, and its emergence was explained by an enhancement of the hopping conductivity due to the EPR-induced temperature increase mechanism. No EDMR spectra were found to occur in the 6H-SiC crystals with ND–NA≈4×1019cm−3, which is close to the critical donor concentration value for a semiconductor-metal transition. Thus it can be concluded that this N donor concentration is too high for the appearance of spin-dependent scattering and too low for the emergence of EPR-induced hopping mechanisms in 6H-SiC. Published by the American Physical Society 2024

Performance evaluation of inorganic Cs3Bi2I9-based perovskite solar cells with BaSnO3 charge transport layer

This research embedded with a novel idea of integration of perovskite material as charge transport layer corresponding to the perovskite absorber layer. The study explores the effectiveness of BaSnO3 perovskite material as an electron transport layer (ETL) in Cs3Bi2I9-based perovskite solar cells, using SCAPS-1D simulations. The research meticulously examines how structural and optical variations in each layer affect the device’s performance indicators, finding the thickness of the Cs3Bi2I9 layer and its defect concentration pivotal for optimal functionality. The highest photovoltaic efficiency, 20.62%, was achieved with an absorber layer thickness of 0.8 micrometers and acceptor and donor concentrations between 1E17 /cm3 and 1E18 /cm3, respectively. The absorber’s bulk defect density optimally ranged from 1E14 /cm3 to 1E15 /cm3. Interface defects between BaSnO3 and Cs3Bi2I9 layers significantly influenced performance, more so than those at the HTL (Cu2O) interface. The study also assesses thermal effects and series and shunt resistances, aiming to mitigate potential induced degradation (PID), a key concern for solar cell longevity and reliability. Nickel (Ni) was chosen as the back contact metal, balancing cost and efficiency. This research intends to clarify PID conditions to enhance the durability and consistent performance of photovoltaic systems.

Poly(ethylene oxide) bis(cyclic carbonate) based hydrophilic non-isocyanate polyhydroxyurethanes: Polymer-water interactions and glass transition behavior

Hydrogen bonding, glass transition, water absorption, and plasticization are studied as a function of hydrogen bond donor concentration in the chain of a non-isocyanate polyhydroxyurethane system, synthesized by solvent-free aminolysis of a poly(ethylene oxide) (PEO) based cyclic carbonate. The concentration of hydrogen bond donors is controlled by varying the ratio of diaminobutane (DAB) and triethylenetetramine (TETA) in the amine component. Introduction of secondary amino groups enhances hydrogen bonding and rigidity of the chain, and, as a result, slows down dynamics, as evidenced by an increase in glass transition temperature. Hydroxyurethane groups are the primary hydration sites despite the hydrophilicity of the polyether. Secondary amino groups act as secondary hydration sites which further increases water sorption capacity. The Couchman-Karasz model describes excellently the dependence of glass transition temperature on composition in both dry and hydrated systems.

Biopharmaceutical aspects of the development of transdermal forms of Lisinopril dihydrate

Abstract Prevention and treatment of arterial hypertension is of great importance. Improvement of existing medicines through the use of alternative routes of administration can enhance the pharmacotherapeutic characteristics of active pharmaceutical ingredients (APIs). Transdermal therapeutic systems (TTS) allow for delivery of a drug through intact skin into the systemic circulation, while minimizing side effects. The development of transdermal formulations of antihypertensive drugs, Lisinopril dihydrate in particular, has practical and scientific significance. Optimization of the algorithm for the development of transdermal drugs involves in vitro preformulation studies of the membrane permeability of APIs and the identification of factors that affect this process. The tests were performed by dialysis through a semipermeable hydrophilic membrane using a Valia-Chien diffusion device. The effect of the initial concentration of Lisinopril dihydrate on the flux rate I s was investigated. Different donor concentrations of Lisinopril dihydrate were tested at three levels, 10, 20 and 30 mg/ml, accordingly. It was noted that the permeation process of Lisinopril dihydrate under model conditions corresponds to zero-order kinetics and is characterized by a uniform speed. The correlation coefficient (R 2) for all the kinetic equations was 0.999. A linear dependence of the flux velocity of Lisinopril dihydrate on the initial concentration was indicated. The concentration of Lisinopril dihydrate in the donor solution of 30 mg/ml was found to be optimal for further stages of pharmaceutical development of the transdermal formulation. The studies of Lisinopril dihydrate permeability allow to give a positive assessment of the acceptability of this API for use in the transdermal formulation and the development of TTS.

Impact of Zn addition on structural, morphological, and magnetic properties of thermally annealed Li–Zn nanoferrite

The effect of Zn addition on cationic distribution, structural and magnetic properties of nanocrystalline Li-Zn ferrites are reported. X-ray diffraction confirms the formation of spinel nanoferrites with an average grain diameter of 34 − 82 nm. The addition of Zn results in a linear increase of lattice parameter and X-ray density. Magnetism in the studied samples is governed by the Yafet-Kittel three-sub-lattice model, shown by a non-zero canting angle. The variation in magnetic properties is correlated with the calculated cationic distribution. A new antistructural modeling explains the changes in the concentration of donor and acceptor surface active centers.

High quality heavy Sn doping β‑Ga2O3 film with high mobility grown by time division transport Metal Organic Chemical Vapor Deposition

High-quality heavily Sn doped homoepitaxial β-Ga2O3 films with high mobility were deposited on (100) Ga2O3 substrates using long-distance time division transport method by Metal Organic Chemical Vapor Deposition. The structure, composition, Raman, and electrical properties of the films with different Sn source flow rates were investigated in detail. The room temperature carrier mobility of 139.89 cm2/(V·s) is attained at a RT donor concentration of 2.78×1019 cm-3, with a peak mobility of 444.9 cm2/(V·s) at 114 K. This RT mobility is currently the highest at the same doping concentration level. Furthermore, combined with the analysis of the first-principles calculation results, it is revealed that time dependent transport technology is beneficial to modulating the substitution mode of Sn replacing GaII more often. The conclusions of this study are significant to broaden the potential application of ultrawide bandgap gallium oxide in high-power microwave and power electronics devices.

Influence of Doping Engineering in 1 μm Drift Layer Quasi‐Vertical Fin Field‐Effect Transistor for Achieving &gt;139 V Breakdown Voltage

A quasi‐vertical gallium nitride (GaN) fin field effect transistor (FinFET) is designed and analyzed to assess the performance of electrical parameters. The device is deployed on a silicon carbide (SiC) substrate and analyzed using technology computer‐aided design (TCAD). The donor concentration in the critical regions is identified as a significant limiting factor for FinFET electrical properties. Hence, the influence of channel and drift layer doping concentrations (Nd) on performance characteristics is investigated in this work. The electrical characteristics such as threshold voltage, ION/IOFF ratio, subthreshold swing (SS), specific ON‐resistance, and breakdown voltage (VBV) are evaluated for various doping profiles. The doping profile with channel and drift layer concentration of 4 × 1015 cm−3 for a 300 nm fin width and 1 μm thick drift layer exhibits normally OFF behavior with a threshold voltage (Vt) of 1.5 V. It also demonstrates a VBV of 139 V. The corresponding doping profile reveals a low SS of 61 mV dec−1, which is comparable to other similar power devices. This demonstrates the significant potential of the device for medium‐power switching applications.

Excited State Proton Transfer from Acidic Alcohols to a Quinoline Photobase Can Be Solvated by Non-Acidic Alcohol Solvents.

Photobases are a type of molecule that become more basic upon photoexcitation and can therefore be used to control proton transfer reactions with light. The solvation requirements for excited state proton transfer (ESPT) in photobase systems is poorly understood, which limits their applicability. Here, we investigate the solvation of the ESPT reaction using 5-methoxyquinoline (MeOQ), a well-studied photobase with an excited state pKa (pKa*) of approximately 15.1, as a model system. Previous studies have shown that, in addition to the acidic donor that donates a proton to the photoexcited MeOQ, an additional "auxiliary donor" is necessary to solvate the resulting alkoxide. We investigate whether a nonacidic hydrogen bond donor (an alcohol solvent that MeOQ cannot deprotonate in bulk) can act as the auxiliary donor for the MeOQ ESPT reaction. First, we use steady state spectroscopy, TCSPC, and electronic structure calculations to show that MeOQ can deprotonate the acidic donor 2,2,2-trifluoroethanol (TFE, pKa = 12.5) using ethanol as the auxiliary donor. We show that the degree of ESPT is largely predicted by the degree of ground state hydrogen bonding between the photobase and the acidic donor. Next, we study the deprotonation of the acidic donors TFE and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP, pKa = 9.3) with MeOQ in a variety of nonacidic alcohol solvents of varying chain length and branching. MeOQ ESPT occurs to varying extents in all solvents, suggesting that all studied nonacidic alcohols can function as auxiliary donors. We show that the concentration of the acidic donor is strongly correlated with the degree of ESPT. These results are necessary fundamental steps toward the understanding of the photobase ESPT reaction and its wide application in a variety of chemical systems.

Characterizing parameter variations for enhanced performance and adaptability in 3 nm MBCFET technology

With the continuous scaling down of semiconductor devices, traditional transistor architectures face significant challenges in maintaining performance and power efficiency. Multi-bridge channel field-effect transistors (MBCFETs) are promising candidates for next-generation of transistors, enabling significant size reduction while preserving high performance. This paper investigates both n-type and p-type 3-nm MBCFETs with a focus on their behavior under diverse operating conditions. The study examines the influence of doping concentration, sheet thickness, temperature, device width, and the number of sheets, on the device's functionality aiming for high-performance applications. Doping concentrations of acceptors and donors ranging from 1 × 10 15 cm−3 - 9 × 10 17 cm−3 and 1 × 10 17 cm−3 - 9 × 10 19 cm−3, respectively, to observe their impact on device performance. Similarly, sheet thicknesses from 1 nm to 2 nm and device widths from 3 nm to 30 nm are analyzed to understand the scaling effects. The temperature varies from 273.15 K to 573.15 K to simulate different operational environments, while the number of sheets, ranging from 1 to 7, is adjusted to evaluate structural effects on device behavior. By extracting the subthreshold swing (SS), threshold voltage (Vth), ON-current (ION), OFF-current (IOFF), and the ION/IOFF ratio, the study offers valuable insights into the suitability and potential applications of N-MBCFET and P-MBCFET devices at the ultra-scaled 3 nm dimension. At room temperatures, the SS achieves 60 mV dec⁻1 for n-type and 64 mV dec⁻1 for p-type which indicates proper switching speed, with corresponding ON/OFF ratios of 2 × 106 and 1 × 105 for n-type and p-type, respectively. This study makes notable contributions to the field of nanoscale transistor technology, aiding in the design and optimization of future electronic devices.

Copper Is Accumulated as Copper Sulfide Particles, and Not Bound to Glutathione, Phytochelatins or Metallothioneins, in the Marine Alga Ulva compressa (Chlorophyta).

To analyze the mechanism of copper accumulation in the marine alga Ulva compressa, it was cultivated with 10 μM of copper, with 10 μM of copper and increasing concentrations of a sulfide donor (NaHS) for 0 to 7 days, and with 10 μM of copper and a concentration of the sulfide acceptor (hypotaurine) for 5 days. The level of intracellular copper was determined as well as the level of glutathione (GSH) and phytochelatins (PCs) and the expression of metallothioneins (UcMTs). The level of intracellular copper in the algae treated with copper increased at day 1, slightly increased until day 5 and remained unchanged until day 7. The level of copper in the algae cultivated with copper and 100 or 200 μM of NaHS continuously increased until day 7 and the copper level was higher in the algae cultivated with 200 μM of NaHS compared to 100 μM of NaHS. In contrast, the level of intracellular copper decreased in the algae treated with copper and hypotaurine. The level of intracellular copper did not correlate with the level of GSH or with the expression of UcMTs, and PCs were not detected in response to copper, or copper and NaHS. Algae treated with copper and with copper and 200 μM of NaHS for 5 days were visualized by TEM and the elemental composition of electrondense particles was analyzed by EDXS. The algae treated with copper showed electrondense particles containing copper and sulfur, but not nitrogen, and they were mainly located in the chloroplast, but also in the cytoplasm. The algae treated with copper and NaHS showed a higher level of electrondense particles containing copper and sulfur, but not nitrogen, and they were located in the chloroplast, and in the cytoplasm. Thus, copper is accumulated as copper sulfide insoluble particles, and not bound to GSH, PCs or UcMTs, in the marine alga U. compressa.