Carrier Profiles Research Articles

Quantification of mobile charge carrier yield and transport lengths in ultrathin film light-trapping ZnFe2O4 photoanodes.

Zinc ferrite (ZnFe2O4, ZFO) has gained attention as a candidate material for photoelectrochemical water oxidation. However, champion devices have achieved photocurrents far below that predicted by its bandgap energy. Herein, strong optical interference is employed in compact ultrathin film (8-14 nm) Ti-doped ZFO films deposited on specular back reflectors to boost photoanode performance through enhanced light trapping, resulting in a roughly fourfold improvement in absorption as compared to films deposited on transparent substrates. The spatial charge carrier collection profile and wavelength-dependent photogeneration yield of mobile charge carriers was then extracted via spatial collection efficiency analysis based on optical and external quantum efficiency measurements. We demonstrate that despite the enhanced performance enabled by the light trapping structure, substantial recombination occurs for thin film ZFO photoanodes even within the space charge region of an ultrathin film photoanode. Furthermore, the excitation-wavelength-dependent yield of mobile charge carriers in ZFO is shown to be less than unity across the visible spectrum, ultimately limiting the attainable photocurrent density. These results explain the underperformance of ZFO as a photoanode material and suggest that reduction of the mobile charge carrier yield due to the existence of ligand field states is a dominant loss mechanism for metal-oxides containing Fe metal centers with open d-shell configuration.

Newborn Screening for Six Primary Conditions in a Clinical Setting in Morocco.

A retrospective investigation was carried out to examine the outcomes of NBS in Casablanca, Morocco. A total of 5511 newborn blood samples were collected via heel-prick sampling and tested for the above disorders. Most of the samples were collected within the third and sixth days of birth. The dried blood spots were analyzed via a quantitative immunofluorescence technique and isoelectric focusing. A total of 72 newborns had one of the six pathological conditions. The most prevalent disorders were hemoglobinopathies, which were identified in 47 newborns (0.9%), with 29 having HbC carrier status (0.5%), 15 having Hb S carrier status (0.3%), and 3 having an Hb Bart's carrier profile (0.05%). This was followed by G6PD deficiency, which was found to affect 16 newborns (0.32% of cases). CF was found in one case (0.02%), whereas five newborns (0.09%) tested positive for CAH. Additionally, two newborns (0.04%) tested positive for CH, and one newborn tested positive for PKU (0.02%). Our findings underscore the importance and success of NBS programs in preventing morbidity and mortality and improving the quality of life of affected neonates. The significant gap in data and research on these disorders within the Moroccan population highlights the urgent need to integrate NBS into routine practice in diagnostic laboratories across Morocco. This integration is crucial for enhancing the health and well-being of Moroccan newborns.

Differential Hall Effect Metrology for Electrical Characterization of Advanced Semiconductor Layers

Semiconductor layers employed in fabricating advanced node devices are becoming thinner and their electrical properties are diverging from those established for highly crystalline standards. Since these properties also change as a function of depth within the film, accurate carrier profiling solutions are required. The Differential Hall Effect (DHE) technique has the unique capability of measuring mobility and carrier concentration (active carriers) through the depth of a semiconductor film. It comprises making successive sheet resistance and sheet Hall coefficient measurements as the thickness of the electrically active layer at a test region is reduced through successive material removal steps. Difference equations are then used to process the data and plot the desired depth profiles. The fundamentals of DHE were established in 1960s. Recently, the adaption of electrochemical processing for the material removal steps, and the integration of all other functionalities in a Differential Hall Effect Metrology (DHEM) tool, has made this technique more practical and accurate and improved its depth resolution to a sub-nm range. In this contribution, we review the development history of this important technique and present data from recent characterization work carried out on Si, Ge and SiGe layers.

A description of variant transthyretin amyloidosis (ATTRv) stage 1 patients and asymptomatic carriers in Spain: the EMPATIa study

BackgroundVariant transthyretin amyloidosis (ATTRv) is a rare multisystemic disorder caused by mutations in the transthyretin (TTR) gene. The aim of the present work was to describe the clinical profile of asymptomatic carriers (AC) and Coutinho stage 1 ATTRv patients in Spain.MethodsNational, multicentre, cross-sectional study that included 86 AC and 19 patients diagnosed in the previous 12 months to enrolment. Clinical and demographical data, TTR gene mutations, red flags anamnesis, neurological and cardiological assessments were collected.ResultsThe mean age of patients was 56.8 years at onset and 58.6 years at diagnosis; 53% of patients and 51% of AC were from non-endemic areas. Val50Met was the most frequent mutation in both groups. Neuropathy impairment score data (mean 17.7 ± 20.5) and small-fibre function in lower limbs assessed with SUDOSCAN revealed that patients were diagnosed at early stages of neurological impairment. Peripheral polyneuropathy (84.2%), autonomic neuropathy (73.7%), cardiac (63.2%) and gastrointestinal (47.4%) alterations were the most common symptoms in patients. Autonomic neuropathy, gastrointestinal impairment, carpal tunnel syndrome, cardiac and ocular alterations were potentially related to ATTRv in the AC group.ConclusionsThe EMPATIa study provides a detailed description of AC and Coutinho stage 1 ATTRv patients across Spain, confirming the multisystemic clinical profile of the disease. This study reveals a diagnosis delay around 1.8 years, highlighting the importance of a profound disease awareness to reach a diagnose in earlier stages of neurological impairment.

Alteration in folate carrier expression via histone deacetylase inhibition in BeWo human placental choriocarcinoma cells

Folates are essential nutrients for fetal development during pregnancy. Valproic acid (VPA), an inhibitor of histone deacetylases (HDACs), alters the expression of folate carriers in placental cells; however, the underlying mechanisms remain unclear. Here, we aimed to determine the profiles of folate carriers (folate receptor alpha [FOLR1], solute carrier [SLC]-19A1, and SLC46A1) after inhibition of HDACs, especially class I and IIa HDACs, using different inhibitors and gene knockdown tests. Quantitative polymerase chain reaction revealed that BeWo cells (a trophoblast model) expressed HDACs and folate carriers, similar to human placental villi. FOLR1 expression was upregulated by VPA, apicidin, and trichostatin A, but downregulated by MS-275 after 24 h treatment. VPA and apicidin upregulated the expression of SLC46A1. These inhibitors downregulated SLC19A1 expression. TMP269 (a class IIa inhibitor) did not affect folate carrier levels. HDAC1/2 knockdown upregulated FOLR1 and SLC46A1 levels, whereas HDAC1/3 knockdown downregulated FOLR1 levels. Our findings suggest that the pharmacological inhibition of class I HDACs alters the expression of folate carriers in BeWo cells. By contrast, HDAC inhibitors exert different regulatory effects on folate carriers. Moreover, HDAC1/2 inhibition may be a potential mechanism involved in altering FOLR1 and SLC46A1 levels.

PEGylation in Pharmaceutical Development: Current Status and Emerging Trends in Macromolecular and Immunotherapeutic Drugs.

The purpose of the research is to examine the advantages and difficulties of target-site drug delivery methods, with an emphasis on the application of polyethylene glycol (PEG) to enhance drug solubility, bioavailability, and immune response characteristics. It has been demonstrated that this method lowers immunogenicity, enhances pharmacokinetics, and helps drugs pass the blood-brain barrier while reducing reticuloendothelial system clearance. PEG and its derivatives are being used more and more to alter therapeutic substances, offering an escape from some of the drawbacks of conventional medication formulations. In the review, different PEGylation tactics are examined, including cutting-edge methods for reversing multi-drug resistance in nanocarriers. PEGylation has a number of benefits, but there are still drawbacks, including the immunogenic reaction to PEG, which is sometimes referred to as "anti-PEG antibodies," and stability problems that call for the creation of countermeasures. The study devotes a large amount of its space to listing FDA-approved PEGylated medications, emphasizing their therapeutic advantages and clinical uses in a range of medical specialties. The research also explores the regulatory environment that surrounds PEG, closely examining its effectiveness and safety in medication compositions. The review goes beyond PEGylation and includes lipid-based nanocarriers, including liposomes, nanostructured lipid carriers (NLCs), and solid lipid nanoparticles (SLNs). Because these nanocarriers can target specific tissues or cells, improve bioavailability, and encapsulate pharmaceuticals, they are becoming more and more significant in drug delivery systems. The Target Product Profile (TPP) and Quality by Design (QbD) principles serve as the foundation for the creation and characterization of these lipid-based systems. These tools direct the methodical assessment of material properties and risk assessments during the formulation phase. This method guarantees that the finished product satisfies the appropriate requirements for efficacy, safety, and quality. The regulatory status and safety profile of nano lipid carriers are covered in the paper's conclusion, which emphasizes the importance of careful examination and oversight in bringing these cutting-edge products to market. Overall, this thorough analysis highlights the revolutionary potential of lipid-based nanocarriers and PEGylation in improving drug delivery and therapeutic efficacy, but it also draws attention to the continued difficulties and legal issues that need to be resolved in order to fully reap the benefits of these technologies in biomedicine.

Analytical Model for Current-Voltage Characteristics in Perovskite Solar Cells Incorporating Bulk and Surface Recombination.

The effects of surface recombination on the steady-state carrier profiles and photocurrent in perovskite solar cells are investigated in this paper. The continuity equations for both holes and electrons are solved considering carrier drift and diffusion under the exponential carrier generation profile in the perovskite layer and considering both bulk and interface carrier recombination. An analytical expression for the solar-induced photocurrent is derived. The rate of carrier recombination at the interfaces has a very significant effect on the carrier profile, photocurrent, and, hence, on the charge collection efficiency. The external current density is calculated considering the dark current and nominal solar spectrum-induced photocurrent. The proposed model is fitted and verified with published experimental results from various publications. The fittings of the model with experimental results provide information about the interface and bulk charge carrier transport parameters.

Optimizing Length Scalability of InGaZnO Thin‐Film Transistors through Lateral Carrier Profile Engineering and Negative ΔL Extension Structure

AbstractThe lateral carrier profile of amorphous indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) plays a significant role in determining the effective channel length (Leff) and length scalability even when the physical gate length (Lg) is the same. Especially, devices with high carrier concentration that have a high mobility of 14.54 cm2 V·s−1 suffer from severe short channel effects at Lg = 1 µm due to the reduced Leff. The current work proposes a systematic methodology for optimizing length scalability for a given Lg that involves engineering of the lateral carrier profile. Unique lateral carrier profiles are extracted using contour maps of ΔL and RSD as a function of carrier profile parameters, and they are validated by comparing the measured Leff, drain‐to‐source resistance, and current‐voltage characteristics with the results of simulations using the extracted carrier profiles. Further, to overcome the trade‐off between enhanced mobility and degraded VT roll‐off that occurs with increasing carrier concentration, an IGZO TFT with gate‐insulator shoulders is fabricated to structurally form negative ΔL and physically increase Leff, while also obtaining a high carrier concentration, ultimately achieving both optimal electrical performance, with mobility of 17.50 cm2 V·s−1, and complete control of the electrostatic integrity of the gate.

The Elemental Composition Investigation of Silicon Doped with Gallium and Antimony Atoms

This work is devoted to the development of a diffusion technology for creating gallium antimonide (GaSb)-type complexes in the silicon crystal lattice as well as to the study of the electrical characteristics of the resulting layers. Based on the X-ray spectral analysis of the microcrystals formed on a silicon sample surface that was simultaneously doped with gallium and antimony atoms, it was demonstrated that the sample surface layer contains microcrystals having silicon, gallium, and antimony atoms. This allowed to admit a possibility of the oriented growth of crystals of the composition (GaSb)0.8Si0.2 on the silicon surface. A substantial impact of the processes of the complex formation that occured at high concentrations of ions of diffusing impurities on the distribution profile of charge carriers is demonstrated. Materials containing GaSb-type complexes in the bulk of the silicon lattice can be produced using ion doping, simultaneous diffusion, or epitaxy processes.

Arsenic Diffusion in MOVPE‐Grown GaAs/Ge Epitaxial Structures

AbstractGermanium is reemerging as a prominent material in the semiconductor field, particularly for electronic applications, photonics, photovoltaics, and thermophotovoltaics. Its combination with III‐V compound semiconductors through epitaxial growth by metal‐organic vapor phase epitaxy (MOVPE) is instrumental and thus, the comprehension of the sequential stages in such epitaxial processes is of great importance. During the deposition of GaAs on p‐type Ge, the formation of n/p junctions occurs when As diffuses into Ge. It is found that this formation begins in the so‐called AsH3 preexposure where Ge substrate is first exposed to AsH3. Also important is the fact that both free carrier profiles and As profiles indicate that prolonged AsH3 preexposure times lead to deeper diffusion depths for the same process time. This effect is concomitant with the degradation of the Ge surface morphology, characterized by higher roughness as the AsH3 preexposure duration is extended. Unlike ion‐implanted As in Ge, which shows a quadratic dependent diffusivity, this MOVPE investigation using AsH3 indicates a linear relationship, consistent with Takenaka et al.’s MOVPE study using TBAs. The analysis of As profiles alongside simulations, with and without subsequent GaAs epitaxy, suggests the generation of Ge vacancies during the process, contributing to deeper As diffusion.

Multiple-carrier-lifetime model for carrier dynamics in InGaN/GaN LEDs with a non-uniform carrier distribution

We introduce a multiple-carrier-lifetime model (MCLM) for light-emitting diodes (LEDs) with non-uniform carrier distribution, such as in multiple-quantum-well (MQW) structures. By employing the MCLM, we successfully explain the modulation response of V-pit engineered MQW LEDs, which exhibit an S21 roll-off slower than −20 dB/decade. Using the proposed model and employing a gradient descent method, we extract effective recombination and escape lifetimes by averaging the carrier behavior across the quantum wells. Our results reveal slower effective carrier recombination and escape in MQW LEDs compared with LEDs emitting from a single QW, indicating the advantages of lower carrier density achieved through V-pit engineering. Notably, the effective carrier recombination time is more than one order of magnitude lower than the effective escape lifetime, suggesting that most carriers in the quantum wells recombine, while the escape process remains weak. To ensure the reliability and robustness of the MCLM, we subject it to a comprehensive threefold validation process. This work confirms the positive impact of spreading carriers into several quantum wells through V-pit engineering. In addition, the MCLM is applicable to other LEDs with a non-uniform carrier distribution, such as micro-LEDs with significant surface recombination and non-uniform lateral carrier profiles.

Amino acid derivative of probenecid potentiates apoptosis-inducing effects of vinblastine by increasing oxidative stress in a cancer cell-specific manner

Many chemotherapeutic drugs suffer from multidrug resistance (MDR). Efflux transporters, namely ATP-binding cassettes (ABCs), that pump the drugs out of the cancer cells comprise one major reason behind MDR. Therefore, ABC inhibitors have been under development for ages, but unfortunately, without clinical success. In the present study, an l-type amino acid transporter 1 (LAT1)-utilizing derivative of probenecid (PRB) was developed as a cancer cell-targeted efflux inhibitor for P-glycoprotein (P-gp), breast cancer resistant protein (BCRP) and/or several multidrug resistant proteins (MRPs), and its ability to increase vinblastine (VBL) cellular accumulation and apoptosis-inducing effects were explored. The novel amino acid derivative of PRB (2) increased the VBL exposure in triple-negative human breast cancer cells (MDA-MB-231) and human glioma cells (U-87MG) by 10–68 -times and 2-5-times, respectively, but not in estrogen receptor-positive human breast cancer cells (MCF-7). However, the combination therapy had greater cytotoxic effects in MCF-7 compared to MDA-MB-231 cells due to the increased oxidative stress recorded in MCF-7 cells. The metabolomic study also revealed that compound 2, together with VBL, decreased the transport of those amino acids essential for the biosynthesis of endogenous anti-oxidant glutathione (GSH). Moreover, the metabolic differences between the outcomes of the studied breast cancer cell lines were explained by the distinct expression profiles of solute carriers (SLCs) that can be concomitantly inhibited. Therefore, attacking several SLCs simultaneously to change the nutrient environment of cancer cells can serve as an adjuvant therapy to other chemotherapeutics, offering an alternative to ABC inhibitors.

Phenotypic profiling of solute carriers characterizes serine transport in cancer

Serine is a vital amino acid in tumorigenesis. While cells can perform de novo serine synthesis, most transformed cells rely on serine uptake to meet their increased biosynthetic requirements. Solute carriers (SLCs), a family of transmembrane nutrient transport proteins, are the gatekeepers of amino acid acquisition and exchange in mammalian cells and are emerging as anticancer therapeutic targets; however, the SLCs that mediate serine transport in cancer cells remain unknown. Here we perform an arrayed RNAi screen of SLC-encoding genes while monitoring amino acid consumption and cell proliferation in colorectal cancer cells using metabolomics and high-throughput imaging. We identify SLC6A14 and SLC25A15 as major cytoplasmic and mitochondrial serine transporters, respectively. We also observe that SLC12A4 facilitates serine uptake. Dual targeting of SLC6A14 and either SLC25A15 or SLC12A4 diminishes serine uptake and growth of colorectal cancer cells in vitro and in vivo, particularly in cells with compromised de novo serine biosynthesis. Our results provide insight into the mechanisms that contribute to serine uptake and intracellular handling.

Multiple TP53 p.R337H haplotypes and implications for tumor susceptibility

The germline TP53 p.R337H mutation is reported as the most common germline TP53 variant. It exists at a remarkably high frequency in the population of southeast Brazil as founder mutation in two distinct haplotypes with the most frequent co-segregating with the p.E134∗ variant of the XAF1 tumor suppressor and an increased cancer risk. Founder mutations demonstrate linkage disequilibrium with neighboring genetic polymorphic markers that can be used to identify the founder variant in different geographic regions and diverse populations. We report here a shared haplotype among Brazilian, Portuguese, and Spanish families and the existence of three additional distinct TP53 p.R337H alleles. Mitochondrial DNA sequencing and Y-STR profiling of Brazilian carriers of the founder TP53 p.R337H allele reveal an excess of Native American haplogroups in maternal lineages and exclusively European haplogroups in paternal lineages, consistent with communities established through male European settlers with extensive intermarriage with Indigenous women. The identification of founder and independent TP53 p.R337H alleles underlines the importance for considering the haplotype as a functional unit and the additive effects of constitutive polymorphisms and associated variants in modifier genes that can influence the cancer phenotype.

Blood Proteome Profiling Reveals Biomarkers and Pathway Alterations in Fragile X PM at Risk for Developing FXTAS.

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a neurodegenerative disorder associated with the FMR1 premutation. Currently, it is not possible to determine when and if individual premutation carriers will develop FXTAS. Thus, with the aim to identify biomarkers for early diagnosis, development, and progression of FXTAS, along with associated dysregulated pathways, we performed blood proteomic profiling of premutation carriers (PM) who, as part of an ongoing longitudinal study, emerged into two distinct groups: those who developed symptoms of FXTAS (converters, CON) over time (at subsequent visits) and those who did not (non-converters, NCON). We compared these groups to age-matched healthy controls (HC). We assessed CGG repeat allele size by Southern blot and PCR analysis. The proteomic profile was obtained by liquid chromatography mass spectrometry (LC-MS/MS). We identified several significantly differentiated proteins between HC and the PM groups at Visit 1 (V1), Visit 2 (V2), and between the visits. We further reported the dysregulated protein pathways, including sphingolipid and amino acid metabolism. Our findings are in agreement with previous studies showing that pathways involved in mitochondrial bioenergetics, as observed in other neurodegenerative disorders, are significantly altered and appear to contribute to the development of FXTAS. Lastly, we compared the blood proteome of the PM who developed FXTAS over time with the CSF proteome of the FXTAS patients recently reported and found eight significantly differentially expressed proteins in common. To our knowledge, this is the first report of longitudinal proteomic profiling and the identification of unique biomarkers and dysregulated protein pathways in FXTAS.

Impact of Depth-Wise Inhomogeneous Iron Distributions on the Accuracy of Lifetime-Based Interstitial Iron Measurements on Silicon Wafers

This article studies the impact of depth-wise inhomogeneous iron distributions in silicon wafers, and the magnitude of the average iron concentrations, on the accuracy of interstitial iron concentrations extracted from effective lifetime measurements on crystalline silicon wafers. The depth-wise inhomogeneous interstitial iron profiles are generated from simulations of gettering of iron to the wafer surfaces, and are therefore practically relevant for silicon solar cells. Our analysis shows that a considerable amount of error can be introduced into the interstitial iron concentration measurement if the iron profiles are highly inhomogeneous, such as in the early stages of gettering. The absolute interstitial iron concentration also has a determinant role on the magnitude of the error. A “threshold” interstitial iron concentration of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> or below (<10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> ) is recommended for defect studies to avoid significant measurement errors. Other effects such as surface passivation, light source spectrum and wafer thickness are found to also affect the accuracy of the interstitial iron concentration measurement by affecting the uniformity of the carrier profiles.

Correlating elemental compositions and charge carrier profiles in ultra-pure GaN/AlGaN stacks grown by molecular beam epitaxy

Inconsistencies in the concentrations of unintentional donor impurities and free charge carriers in GaN/AlGaN layer stacks hosting a two-dimensional electron gas (2DEG) can be attributed to the measurement procedure and solely depend on the way in which the free charge carrier concentration is extracted. Particularly, when the 2DEG acts as the bottom electrode in capacitance versus voltage measurements, unphysically low concentrations of free charges are calculated. This originates from the depletion of the 2DEG and the accompanying disappearance of the bottom electrode. It is shown that, for the case of a defined (non-vanishing) bottom electrode, the levels of donor impurities and resulting free charges consistently match.

Abstract 767: Genomics and transcriptomics profiling of BRCA mutation carriers revealed the landscape of early pathogenesis of BRCA1/2-associated breast cancer

Abstract Women who harbor germline heterozygous mutations of BRCA1 or BRCA2 have a high risk of breast cancer. Our previous study showed that patient-derived, ostensibly normal BRCA2mut/+ luminal progenitor (LP) cells are more prone to exhibit sub-chromosomal copy number variations and associated DNA damage relative to non-carriers potentially reflecting early breast tumorigenesis. The clinically assessable biomarkers for early pathological changes of BRCA1/2 mutation in LP cells remain unknown. Single-cell RNA sequencing (scRNAseq) of LP cells of BRCA1/2 mutation carriers revealed enrichment of KIT expression (KIT+) and subsequent transcriptional factor activations were observed in LP cells of BRCA1/2 mutation carriers relative to non-carriers. Moreover, overrepresented pathway analysis uncovered that KIT+ BRCA-mutated LP cells were enriched in pathways involving DNA binding transcription activator activity and oxidative phosphorylation. These gene signature profiles were recapitulated in bulk RNA-seq of BRCA2 mutation carrier LP cells. Collectively, our preliminary data suggest such analyses may identify potential biomarkers of the risk prediction for early pathogenesis of BRCA1/2 mutation carriers. Following validation of our findings via tissue microassay analysis and clinical trials, we hope to eventually assist clinicians in their decision making of prophylactic surgeries for BRCA1/2 mutation carriers. Citation Format: Zuen Zen, Po-Han Lin, Siang Boon Koh, Kai Stewart, Nick Haradhvala, Aylin S Dedeoglu, Ilze Smidt, Akiko Suzuki, David Li, Win Thant, Sarah Mueller, Taisha Joseph, Veerle Bossuyt, Michael Lawrence, Gad Getz, Leif W. Ellisen. Genomics and transcriptomics profiling of BRCA mutation carriers revealed the landscape of early pathogenesis of BRCA1/2-associated breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 767.

Исследование отражения плоской электромагнитной волны от неоднородного плазменного слоя, расположенного на идеально проводящей плоскости

A method for numerical modelling of the reflection of an electromagnetic wave from a planar plasma layer with an inhomogeneous electron density of particles covered of an ideally conducting plane is proposed in the work. The frequency responses of wave reflection coefficients modules are calculated for various incidence angles and electron density profiles of carriers using the differential sweep method. The paper shows that in the region of plasma resonance the plasma layer with a parabolic profile of charge carrier concentration has the lowest reflection level. The effect of the effective frequency of electron collisions in an inhomogeneous plasma layer on the reflection level was studied in this work.

Optical Modeling of Plasmonic Nanoparticles with Electronically Depleted Layers.

Doped metal oxide (MO) nanocrystals (NCs) are well-known for the localized surface plasmon resonance in the infrared range generated by free electrons in the conduction band of the material. Owing to the intimate connection between plasmonic features and the NC's carrier density profile, proper modeling can unveil the underlying electronic structure. The carrier density profile in MO NCs is characterized by the presence of an electronically depleted layer as a result of the Fermi level pinning at the surface of the NC. Moreover, the carrier profile can be spatially engineered by tuning the dopant concentrations in core-shell architectures, generating a rich plethora of plasmonic features. In this work, we systematically studied the influence of the simulation parameters used for optical modeling of representative experimental absorption spectra by implementing multilayer models. We highlight in particular the importance of minimizing the fit parameters by support of experimental results and the importance of interparameter relationships. We show that, in all cases investigated, the depletion layer is fundamental to correctly describe the continuous spectra evolution. We foresee that this multilayer model can be used to design the optoelectronic properties of core-shell systems in the framework of energy band and depletion layer engineering.