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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Ultra-thin LPCVD SiN <sub/>x</sub> /n+poly-Si passivated contacts a?? A possibility?
摘要： This work explores the possibility of using ultrathin silicon nitride (SiNx) films with high positive fixed charge in a SiNx/poly-Si passivating contact. The factors including (i) film thickness, (ii) annealing condition (time, temp and ambient) and (iii) surface pre-treatment were optimized to boost the passivation performance of ultrathin LPCVD SiNx films. Our preliminary experiments reveal excellent surface passivation and low recombination current density, Jo (45 fA.cm-2) by ~1.5 nm thick LPCVD SiNx films when subjected to an air ambient anneal at 800?C for 30 mins. This is due to the formation of high positive fixed charge density (1.5 ?10 12 cm-2). Air ambient annealed (465 μs) samples also have a higher lifetime when compared to the forming gas annealed (208 μs) samples. These passivating SiNx films were further integrated into SiNx/n+poly-Si contacts and characterized for Jo,contact and tunneling resistance, ?contact. The best SiNx/n+poly-Si passivated contact in this study has Jo, contact = 5.9 fA.cm-2, ?contact = 0.525 Ω.cm2 and an efficiency potential > 22.75%. According to our knowledge, it is the first report confirming the formation of passivated contacts with SiNx as the dielectric tunnel layer.
关键词： poly-Si,TEM,LPCVD SiNx,annealing,lifetime studies,passivated contact,silicon nitride,tunnel layer
更新于2025-09-23 15:19:57
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In-Line Holography in Transmission Electron Microscopy for the Atomic Resolution Imaging of Single Particle of Radiation-Sensitive Matter
摘要： In this paper, for the first time it is shown how in-line holography in Transmission Electron Microscopy (TEM) enables the study of radiation-sensitive nanoparticles of organic and inorganic materials providing high-contrast holograms of single nanoparticles, while illuminating specimens with a density of current as low as 1–2 e???2s?1. This provides a powerful method for true single-particle atomic resolution imaging and opens up new perspectives for the study of soft matter in biology and materials science. The approach is not limited to a particular class of TEM specimens, such as homogenous samples or samples specially designed for a particular TEM experiment, but has better application in the study of those specimens with differences in shape, chemical composition, crystallography, and orientation, which cannot be currently addressed at atomic resolution.
关键词： TEM,radiation damage,atomic resolution imaging,nanostructured drugs,organic materials,in-line holography,soft matter,single particle imaging
更新于2025-09-23 15:19:57
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Dysprosium activated strontium aluminate phosphor: A potential candidate for WLED applications
摘要： A series of dysprosium activated strontium aluminate phosphors (SrAl2O4:xDy3+: x=0.1, 0.2, 0.3, 0.4 and 0.5 %) are prepared by conventional solid state reaction method. The structure of the prepared phosphors is analyzed by XRD, results confirm that the crystallinity of the synthesized phosphors is monoclinic phase with space group P21. Morphology and microstructure of the synthesized phosphors is analyzed using FESEM and TEM analysis respectively. Optical properties are analyzed by using Raman and PL spectra. The characteristic peak observed at 465 cm-1 corresponds to bending mode of O-Al-O bonds in corners sharing with [AlO4]5- tetrahedral. The strongest PL emission band observed at 470 nm is assigned to 4F9/2 - 6H15/2 transition in blue region under the ultraviolet excitation wavelength of 347 nm. White light is formed by combination of these three colors and is confirmed by CIE chromatic coordinate graph and possible responsible mechanism is explained in detail.
关键词： Raman,SrAl2O4:Dy3+,PL,XRD,TEM,CIE,FESEM
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Singapore (2018.7.16-2018.7.19)] 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Application of Si Plasmon Imaging in Semiconductor Failure Analysis
摘要： In this paper, we demonstrate the various applications of the ETEM Si plasmon imaging technique in semiconductor failure analysis. The mechanism of the plasmon imaging will be discussed briefly, then followed by four case studies. The capability of Si plasmon imaging to distinguish the silicon oxide (e.g. gate oxide) and the silicon materials (e.g. poly gate and substrate) is its key advantage over the conventional imaging techniques. Si plasmon imaging not only can identify the defective residues but also can be performed at high magnification to investigate the gate oxide and its interfaces with poly or substrate.
关键词： Silicon plasmon imaging,energy filtered TEM,high resolution TEM
更新于2025-09-19 17:15:36
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Combined microscopy and spectroscopy techniques to characterize a fossilized feather with minimal damage to the specimen
摘要： The study of fossil feathers has been revitalized in the last few decades and has contributed significantly to paleontological studies of dinosaurs and birds. Specific morphological and physicochemical characteristics of the microscale structures of feathers and the protein keratin are key targets when preserved during the fossilization process. Keratin is a fibrous protein that composes some hard tissues such as hair, nails and feathers. It is part of the so called intermediate filaments inside keratinocyte cells and is rich in sulfur containing amino acid cysteine. To date, different microscopy and analytical methods have been used for the analysis and detailed characterization and classification of feathers. However, in this work we showed that analytical optical and electron microscopies can be quick and precise methods with minimal effects on the sample during analysis. This association of different approaches on the same sample results in correlative data albeit in different length scales. Intracellular bodies called melanosomes originally present in melanocyte cells were identified with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), and had well-defined orientation and a mean aspect ratio comparable to melanosomes extant in dark feathers. The detection of sulphur in melanosomes via Energy Dispersive Spectroscopy both in SEM and TEM shows that, along the fossilization process, sulphur from the degraded keratin matrix could have been trapped inside the melanosomes. Chemical groups that make up keratin and melanin in the fossil sample were detected via FT-IR Spectroscopy and Confocal Laser Scanning Microscopy (CLSM). The use of combined analytical microscopy techniques can contribute significantly to the study of fossils generating precise results with minimum damage to the original sample.
关键词： EDS,Crato Formation,TEM,CLSM,FT-IR Spectroscopy,SEM
更新于2025-09-19 17:15:36
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Organic Fractal Nano-Dimensional Structures Based on Fullerene C <sub/>60</sub>
摘要： The ways for a synthesis of nanoporous and close-packed types of fullerene C60 aggregates in two-component organic solvents (toluene + tetrahydrofuran) were established as well as their structural and dimensional features - were studied by high-resolution transmission electron microscopy and atomic-force microscopy methods. The physical features and regularities that characterize the processes of self-organization of fullerene molecules in the initial molecular solution were determined. The method for producing nanoscale fullerene C60 fractal coatings (thickness up to ~1200 nm) on a flat dielectric glass surface was proposed.
关键词： self-assembles,AFM,solvent,fullerene C60,TEM,fractal,nanocoating
更新于2025-09-19 17:15:36
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Atomic Scale Imaging of Reversible Ring Cyclization in Graphene Nanoconstrictions
摘要： We present an atomic level study of reversible cyclization processes in suspended nanoconstricted regions of graphene that form linear carbon chains (LCCs). Before the nanoconstricted region reaches a single linear carbon chain (SLCC), we observe that a double linear carbon chain (DLCC) structure often reverts back to a ribbon of sp2 hybridized oligoacene rings, in a process akin to the Bergman rearrangement. When the length of the DLCC system only consists of ～5 atoms in each LCC, full recyclization occurs for all atoms present, but for longer DLCCs we find that only single sections of the chain are modified in their bonding hybridization and no full ring closure occurs along the entire DLCCs. This process is observed in real time using aberration-corrected transmission electron microscopy and simulated using density functional theory and tight binding molecular dynamics calculations. These results show that DLCCs are highly sensitive to the adsorption of local gas molecules or surface diffusion impurities and undergo structural modifications.
关键词： Bergman rearrangement,carbon chains,graphene constrictions,aberration-corrected TEM
更新于2025-09-19 17:15:36
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Triple stimuli-responsive ZnO quantum dots-conjugated hollow mesoporous carbon nanoplatform for NIR-induced dual model antitumor therapy
摘要： Aiming at the inef?ciency and toxicity in traditional antitumor therapy, a novel multifunctional nanoplat-form was constructed based on hollow mesoporous carbon (HMC) to achieve triple stimuli response and dual model antitumor therapy via chemo-photothermal synergistic effect. HMC was used as an ideal nanovehicle with a high drug loading ef?ciency as well as a near-infrared (NIR) photothermal conversion agent for photothermal therapy. Acid-dissoluble, luminescent ZnO quantum dots (QDs) were used as the proper sealing agents for the mesopores of HMC, conjugated to HMC via disul?de linkage to prevent drug (doxorubicin, abbreviated as Dox) premature release from Dox/HMC-SS-ZnO. After cellular endocytosis, the Dox was released in a pH, GSH and NIR laser triple stimuli-responsive manner to realize accurate drug delivery. Moreover, the local hyperthermia effect induced by NIR irradiation could promote the drug release, enhance cell sensitivity to chemotherapeutic agents, and also directly kill cancer cells. As expected, Dox/HMC-SS-ZnO exhibited a high drug loading capacity of 43%, well response to triple stimuli and excellent photothermal conversion ef?ciency g of 29.7%. The therapeutic ef?cacy in 4T1 cells and multicellular tumor spheroids (MCTSs) demonstrated that Dox/HMC-SS-ZnO + NIR had satisfactory chemo-photothermal synergistic effect with a combination index (CI) of 0.532. The cell apoptosis rate of the combined treatment group was more than 95%. The biodistribution and pharmacodynamics studies showed its biosecurity to normal tissues and synergistic inhibition effect to tumor cells. These distinguished results indicated that the Dox/HMC-SS-ZnO nanoplatform is potential to realize ef?cient triple stimuli-responsive drug delivery and dual model chemo-photothermal synergistic antitumor therapy.
关键词： Chemo-photothermal synergistic therapy,Triple stimuli-responsive,Hollow mesoporous carbon nanoparticles,TEM-EDX mapping,ZnO quantum dots
更新于2025-09-19 17:13:59
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Performance of TiO2 Based Dye-Sensitized Solar Cells Fabricated Using Coomassie Brilliant Blue in Acetonitrile Solution
摘要： The synthetic dye sensitizer based solar cells were successfully fabricated and photovoltaic performance was measured. Titanium dioxide (TiO2) nanoparticles were synthesized using sol–gel technique. The XRD and HRTEM analysis were carried out to determine the structural and morphological property of TiO2 nanoparticles. The crystalline sizes of the TiO2 particles were determined by XRD and were confirmed by TEM. The synthetic Coomassie Brilliant Blue (CBB) dissolved in acetonitrile was used as a dye in the nanocrystalline Tio2 solar cell. TiO2 films on FTO glass substrate were prepared by simple doctor blade technique. The dye was characterized by UV-Vis absorption spectroscopic analysis. The strong absorption of the CBB dye enhanced the DSSC property. The results showed that TiO2 as photoanode and CBB as a sensitizers showed good conversion efficiency.
关键词： CBB,DSSC,TEM,XRD,Titanium dioxide
更新于2025-09-19 17:13:59
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Fabrication of silicon carbide nanoparticles using picosecond pulsed laser ablation in acetone with characterizations from TEM and XRD
摘要： We fabricated SiC nanoparticles (NPs) using a laser ablation method in acetone with a picosecond pulsed laser and characterized the resulting sizes, shapes, and crystal structures using transmission electron microscopy (TEM) and X-ray diffraction (XRD). We revealed two formation processes for the SiC NPs. The main process was the formation of spherical NPs with diameters primarily less than 10 nm. The crystal structure was 3C-SiC, which did not depend on a target polytype. Therefore, it is concluded that these NPs are grown from atomic molecules that disassociate from targets in the ablation process. As a result of a Rietbelt analysis of the XRD patterns, we clearly found that almost all NPs were single crystals. In addition, a stacking fault in the crystal was observed in the TEM image, which affects the XRD pattern. The other process was the formation of NPs with diameters from 30 to 80 nm with crystal structures that were the same as the targets. This indicates that these NPs were generated as fragments of the target. Our findings are useful for applications of SiC NPs to selectively control their size, shape, and crystal structure using laser ablation.
关键词： silicon carbide nanoparticles,3C-SiC,picosecond pulsed laser ablation,TEM,XRD
更新于2025-09-19 17:13:59