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[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Femtosecond Laser-assisted Fabrication of Fluorescent Boron Nitride Quantum Dots
摘要： As a kind of heavy metal-free quantum dot, boron nitride quantum dots (BNQDs) have attracted great interest due to their unique optical properties. Although there many synthesis methods of BNQDs, most of them require complex or time-consuming procedures, which limits the application of BNQDs. Here, we present a facile synthesizing method of few-layer BNQDs, which is based on liquid-phase ultra-short laser pulse ablation and ultrasonic-assisted exfoliation methods. The fabricated BNQDs are systematically characterized by atomic force microscope, transmission electron microscope, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The products possess an average size of about 2.1 nm with few-layer thickness. Because of the abundant surface functional groups, the BNQDs show bright luminescence emission under UV light irradiation.
关键词： femtosecond laser pulse ablation,ultrasonic-assisted exfoliation,boron nitride quantum dots
更新于2025-09-16 10:30:52
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A novel electrochemiluminescence sensor based on resonance energy transfer system between nitrogen doped graphene quantum dots and boron nitride quantum dots for sensitive detection of folic acid
摘要： Electrochemiluminescence resonance energy transfer (ECL-RET) between quantum dots (QDs) was firstly proposed. In this work, boron nitride quantum dots (BNQDs) as the donor and nitrogen doped graphene quantum dots (NGQDs) as the acceptor were confirmed by the absorption spectrum, the emission spectrum and fluorescence spectrum. Based on the reaction between FA and the SO4?? in the ECL system of NGQDs/BNQDs/K2S2O8, the ECL sensing platform for FA was successfully constructed. Surprisingly, a stable and strong ECL signal was obtained based on the RET, which was used for signal-off detection of FA in the presence of coreactant K2S2O8. Notably, about 10-fold enhancement was observed compared with the absence of BNQDs. The proposed sensor showed wide linear ranges of 1.0 × 10?11 M to 1.0 × 10?4 M and a low detection limit of 5.13 × 10?12 M. Simultaneously, the sensor was successfully applied to detection of FA in human serum samples with excellent recoveries. Therefore, the NGQDs/BNQDs system provided a new perspective for development of novel ECL-RET sensors.
关键词： Folic acid,Nitrogen doped graphene quantum dots,Resonance energy transfer,Boron nitride quantum dots,Electrochemiluminescence
更新于2025-09-16 10:30:52
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Development of aluminum paste with/without boron content for crystalline silicon solar cells
摘要： Improvement of aluminum alloyed p?+?back surface ?elds (p?+?BSF) which is an essential requirement for achieving high ef?ciency silicon solar cells has been an important task. One of the ways to have better quality BSFs can be to introduce screen printable aluminum pastes with boron content. Two type of pastes were developed in this work and recipes were provided in detail: screen-printable aluminum paste without boron content (B-free-Al-paste), screen-printable aluminum paste with boron content (Al-B-paste). The ingredients of the pastes were optimized and basically evaluated in terms of alloying and impurity characteristics by measurement of sheet resistances, carrier lifetimes and SIMS analysis. Carrier lifetimes of the wafers processed by Al-B-paste maintained at around 300 μs relatively higher than the wafers processed by B-free-Al-paste. P-type silicon solar cells were fabricated using developed pastes and were compared with those of the cells fabricated by commercial aluminum pastes. Best ef?ciency of 17.8% was achieved with totally vacuum-less cell production process and Suns-Voc analysis were also carried out for fabricated solar cells.
关键词： silicon solar cell,boron doping,aluminum paste
更新于2025-09-16 10:30:52
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Nd:YAG pulsed laser brazing of cBN to steel matrix with Zr modified Aga??Cua??Ti active brazing alloy
摘要： The study was to investigate the modifying effect of the active element Zr on the properties of mechanical alloyed (MA) AgCu28–4.5Ti brazing alloys, especially the joint performance of cubic boron nitride (cBN)/45 steel brazed with AgCu28–4.5Ti–4Zr active brazing alloy. The brazing process was carried out using an Nd:YAG pulsed laser device under a high purity argon atmosphere. The granularity distribution and composition analysis of the MA brazing alloys, microstructural examinations and phase analysis were performed using a laser granularity analyzer, scanning electron microscopy (SEM) equipped with energy dispersion spectrometry (EDS), and X–ray diffraction (XRD) techniques. The results indicate that the alloy particles are refined, sizes are uniform, and the formation of the hard-brittle phase is reduced owing to the addition of the active element Zr. The wettability of the brazing alloy containing Zr is enhanced. The reaction of the active element Zr with Ag or Cu inhibits the combination of Ti with Ag or Cu under rapid laser heating and cooling, and further promotes the generation of Ti-B and Ti-N compounds. The joining mechanism is derived from the formation of a continuous reaction layer between cBN and the brazed alloy, containing a sub-outer structure of TiB, TiB2, TiN, ZrB2, and an outer structure consisting of AgZr2, Cu10Zr7. This multi-layered structure, which is from cBN to 45 steel, realizes the metallurgy combination of the brazing alloy and cBN particles. The friction and wear tests indicate that the reliable connection of cBN to steel is realized.
关键词： Joint performance,Laser brazing,Active brazing alloy,Cubic boron nitride,Microstructure
更新于2025-09-16 10:30:52
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Controlled surface modification of poly(methyl methacrylate) film by fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica/hexagonal boron nitride nanocomposites
摘要： Fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(CH2CHSi(OMe)3)n-RF; n = 2, 3; RF = CF(CF3)OC3F7] undergoes sol–gel reactions in the presence of hexagonal boron nitride (h-BN) nanoparticles under alkaline or acidic conditions at room temperature to afford the corresponding fluorinated oligomeric silica/h-BN nanocomposites in good isolated yields (≥ 80%), respectively. The fluorinated oligomeric silica/h-BN nanocomposites thus obtained were found to exhibit a good dispersibility toward the traditional organic media including water. These two kinds of fluorinated nanocomposites were applied to the surface modification of poly(methyl methacrylate) (PMMA). The fluorinated nanocomposites prepared under alkaline conditions can give not only a good oleophobic characteristic imparted by longer fluoroalkyl groups in the composites but also the higher fluorescent emission related to the presence of h-BN on the only surface side of the modified PMMA film. In contrast, the fluorinated nanocomposites prepared under acidic conditions can provide a good oleophobic characteristic and a higher fluorescent emission on both the surface and even on the reverse side of the PMMA film. Such unique controlled surface modification ability will be discussed by 29Si solid-state NMR spectra of these two types of the nanocomposites.
关键词： Surface arrangement ability,Fluorescent ability,Oleophobicity,Hexagonal boron nitride,Surface modification,Fluorinated oligomeric nanocomposite,PMMA
更新于2025-09-16 10:30:52
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Investigation of boron-doped hydrogenated silicon films as a thermo-sensing layer for uncooled microbolometer
摘要： Boron-doped hydrogenated silicon films are used in thermo-sensing layer in infrared detectors or uncooled microbolometers. Among thermo-sensing materials such as vanadium oxide and amorphous silicon and silicon diodes, amorphous silicon is the most common. Parameters such as the temperature coefficient of resistance (TCR), sheet resistance and 1/f noise are very important for the performance of these devices. One thermo-sensing material in particular, boron-doped hydrogenated silicon (BSi:H), has satisfactory TCR, sheet resistance (Rsheet), and 1/f noise values. The BSi:H films are deposited using radio frequency plasma-enhanced chemical vapor deposition. The dependence of electrical, structural, and chemical properties of the BSi:H films on the plasma parameters is reported. The TCR of the films is 1.0 - 2.9 %/K, Rsheet is 1.2 - 37.8 MΩ/□ and crystalline volume fraction is 10.2 - 68.5%. The properties of the amorphous and mixed-phase are compared. It is found that the 1/f noise of the mixed-phase film is lower than that of the amorphous phase film. These results show that the boron doped mixed-phase silicon films are suitable for use as thermo-sensing layers.
关键词： mixed-phase,thermo-sensing layer,uncooled microbolometer,boron-doped hydrogenated silicon films
更新于2025-09-16 10:30:52
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Investigation of p+ emitter formation for n-type silicon solar cells application
摘要： Investigation of p+ emitter formation for n-type silicon solar cells application. This work reports on the study of boron diffusion in n-type silicon from preform source for p+ emitter formation. Using quartz tube furnace, three main parameters are investigated that are: drive-in temperature, drive-in time and temperature ramp-up time. It is found that the sheet resistance as measured by the four point probe method (4-pp) decreases from 93 Ω/□ to 24 Ω/□ as the drive-in temperature increases from 850°C to 950°C, likewise, it decreases from 57 Ω/□ to 38 Ω/□ as the drive-in time increases from 20 min to 40 min. The electrically active boron dopant profiles as measured by the electrochemical capacitance voltage technique (ECV) exhibit surface concentrations below the solid-solubility limit of boron in silicon for all the studied emitters, the maximum surface and peak boron concentrations of 1.30x1020 and 1.58x1020 atoms/cm3 were measured respectively on the emitter which is formed at a drive-in temperature of 950°C. Furthermore, it is revealed from the secondary ion mass spectroscopy measurements (SIMS) the presence of the boron rich layer (BRL) on its surface. The Hall Effect measurement method is used for measuring sheet resistance and sheet charge carrier concentration.
关键词： N-type silicon,Boron dopant profile,Solar cells,Preform source,Boron diffusion
更新于2025-09-12 10:27:22
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Probing Polaritons in 2D Materials with Synchrotron Infrared Nanospectroscopy
摘要： Polaritons, which are quasiparticles composed of a photon coupled to an electric or magnetic dipole, are a major focus in nanophotonic research of van der Waals (vdW) crystals and their derived 2D materials. For the variety of existing vdW materials, polaritons can be active in a broad range of the electromagnetic spectrum (meVs to eVs) and exhibit momenta much higher than the corresponding free-space radiation. Hence, the use of high momentum broadband sources or probes is imperative to excite those quasiparticles and measure the frequency-momentum dispersion relations, which provide insights into polariton dynamics. Synchrotron infrared nanospectroscopy (SINS) is a technique that combines the nanoscale spatial resolution of scattering-type scanning near-field optical microscopy with ultrabroadband synchrotron infrared radiation, making it highly suitable to probe and characterize a variety of vdW polaritons. Here, the advances enabled by SINS on the study of key photonic attributes of far- and mid-infrared plasmon- and phonon-polaritons in vdW and 2D crystals are reviewed. In that context the SINS technique is comprehensively described and it is demonstrated how fundamental polaritonic properties are retrieved for a range of atomically thin systems including hBN, MoS2, graphene and 2D heterostructures.
关键词： s-SNOM,hexagonal boron nitride,far-infrared SINS,2D materials,polaritons,infrared synchrotron nanospectroscopy,graphene
更新于2025-09-12 10:27:22
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Full Activation of Boron in Silicon Doped by Self-assembled Molecular Monolayers
摘要： The self-assembled molecular monolayer (SAMM) doping has great potential in state-of-the-art nanoelectronics with unique features of atomically precision and non-destructive doping on complex 3D surfaces. However, it was recently found that carbon impurities introduced by the SAMM significantly reduced the activation rate of phosphorus dopants by forming majority carrier traps. Developing a defect-free SAMM doping technique with a high activation rate for dopants becomes critical for reliable applications. Considering that susbstitutional boron does not interact with carbon in silicon, herein we employ Hall measurements and secondary ion mass spectrometry (SIMS) to investigate boron activation rate, and then deep level transient spectroscopy (DLTS) and minority carrier transient spectroscopy (MCTS) to analyze defects in boron-doped silicon by the SAMM technique. Unlike the phosphorus dopants, the activation rate of boron dopants is close to 100%, which is consistent with the defect measurement results (DLTS and MCTS). Only less than 1% boron dopants bind with oxygen impurities, forming majority hole traps. Interestingly carbon-related defects in form of CsH and CsOH act as minority trap states in boron-doped silicon which will only capture electrons. As a result, the high concentration of carbon impurities have no impact on the activation rate of boron dopants.
关键词： boron-doped silicon,Full activation,molecular monolayer doping,carbon-related defects,minority carrier trap
更新于2025-09-12 10:27:22
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Pt Nanoclusters Sandwiched between Hexagonal Boron Nitride and Nanographene as van der Waals Heterostructures for Optoelectronics
摘要： We report on the formation of nanoscopic heterostructures composed of the semimetal graphene, the metal platinum, and the insulator hexagonal boron nitride (h-BN). Both graphene and h-BN are chemically inert 2D materials with similar geometric but different electronic properties. Between these materials, a Pt nanoparticle array was encapsulated. Thereby, the h-BN/Rh(111) nanomesh served as a template for a well-ordered array of Pt nanoclusters, which were overgrown with graphene, forming single nano-heterostructures. We investigated this process in situ by high-resolution, synchrotron radiation-based XPS, and NEXFAS. The nanographene layers proofed tight against CO under the tested conditions. These nano-heterostructures could find a possible application in optoelectronics or as data storage material. At the same time, our approach represents a new route for the synthesis of nanographene.
关键词： nanoclusters,optoelectronics,hexagonal boron nitride,nanographene,data storage,graphene,platinum
更新于2025-09-12 10:27:22