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[IEEE 2019 IEEE 19th International Conference on Nanotechnology (IEEE-NANO) - Macao (2019.7.22-2019.7.26)] 2019 IEEE 19th International Conference on Nanotechnology (IEEE-NANO) - Interface Engineering to Enhance the Photoresponse of Core-Shell Structure Silicon Nanowire Photodetectors
摘要： In this paper, based on fractional calculus, the arbitrary-order fractor is proposed to implement the analog circuit realization of the arbitrary-order Fractional Hop?eld Neural Networks (FHNNs) and the fractor-based FHNNs are ?rst proposed to apply to the hardware security of defense against chip cloning attacks. Since the fractor is the most important circuit component needed to implement the FHNNs, the hardware achievement of the arbitrary-order fractor is the primary task and crux for the state-of-the-art application of the FHNNs to defense against chip cloning attacks. Motivated by this need, based on fractional calculus, the arbitrary-order fractor is proposed to implement the analog circuit realization of the arbitrary-order FHNNs and the fractor-based FHNNs are proposed to apply to defense against chip cloning attacks. The ?rst step is the proposal for the analog circuit realization of an arbitrary-order FHNN. In particular, the hardware achievement of the arbitrary-order net-grid-type capacitive scaling fractor of the arbitrary-order FHNNs is chie?y analyzed in detail. The circuit con?guration of the arbitrary-order net-grid-type scaling fractor can be achieved more convenient than any other discovered approximate implementation of the arbitrary-order fractor. Finally, the approximation performance of the arbitrary-order fractor of the FHNNs is analyzed, the arbitrary-order FHNNs are achieved by analog circuit realization, and its ability of defense against chip cloning attacks is illustrated in detail experimentally. The main contribution of this paper is the proposal for the ?rst preliminary attempt of a feasible hardware implementation of the arbitrary-order FHNNs for defense against chip cloning attacks. Different order FHNNs can be achieved and distributed for different users, respectively. Thus, in a similar way to frequency band, order band can also be allocated ef?ciently that is another emerging promising electronic resource.
关键词： allocation of order band,Fractional calculus,fractance,net-grid-type scaling fractor,defense against chip cloning attacks
更新于2025-09-16 10:30:52
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Grain Size Engineering of Ferroelectric Zr-doped HfO2 for the Highly Scaled Devices Applications
摘要： Ferroelectric Zr-doped HfO2 (HZO) is a promising candidate component for the future transistors and memory devices applications. To address the device-to-device variation in those highly scaled devices, the grain properties of 12-nm-thick HZO films are investigated and optimized by altering the atomic layer deposition (ALD) cycle ratio of HfO2 and ZrO2 at a constant Zr concentration. The largest remanent polarization 2Pr of 41 μC/cm2, refined average grain radius from 16.6 nm to 13 nm, and improved grain size distribution with the standard deviation reduced from 5 to 3.3 are realized by adjusting the ALD cycle ratio to 5/5. Furthermore, the possible underlying mechanisms for the ferroelectric behaviors and the growth modes of the HZO films deposited with various cycle ratios are demonstrated.
关键词： atomic layer deposition,scaling,Ferroelectric transistors,Zr-doped HfO2,grain size engineering
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Coherent Beam Combining by Noncollinear Sum-Frequency Generation
摘要： Despite rapid development of fiber laser technologies, highest pulse peak power achievable from fiber lasers eventually approaches limits which are not easy to overcome. Therefore, there is growing interest in methods, which would allow to combine outputs from multiple pulsed fiber lasers into single diffraction-limited beam, and by this enable further scaling. For this reason, numerous coherent and incoherent beam combining methods are being proposed and investigated. Not so well investigated class of beam combining methods is beam combing based on nonlinear interaction. In our earlier work, we have demonstrated beam combining by multiplexing pulses in time, using second-order nonlinear crystal set in noncollinear phase-matching configuration. However, such configuration allows to scale only average power of the beam, leaving pulse energy unchanged (in case of 50 % conversion efficiency). In order to scale pulse energy and peak power, pulses have to be also combined in time, and for this, phase control is needed. Such approach was first proposed by Michailovas et al. and first proof of concept demonstrated by Zhang et al.. However, in previous demonstrations, low-power beams were combined with very low combining efficiency (<0.4 % for 4 beams). Here we apply this method to more realistic scenario and demonstrate combining of pulsed beams from 4 high-power fiber amplifiers with efficiency up to 49 %. Moreover, we demonstrate pulse energy and peak power improvement in the combined beam, exceeding peak-power limitations of single fiber amplifier.
关键词： noncollinear sum-frequency generation,fiber lasers,pulse energy scaling,peak power scaling,coherent beam combining
更新于2025-09-12 10:27:22
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Simulation Investigation of Laterally Downscaled N-Polar GaN HEMTs
摘要： The N-polar GaN high-electron mobility transistors (HEMTs) have demonstrated a powerful performance as the Ga-polar GaN HEMTs. This investigation aims to show the direct current performance and cutoff frequency (fT) of the planar N-polar GaN HEMTs with gate lengths downscaling from 4 μm to 50 nm by 2-D device simulation. The impacts of traps and gate dielectrics and the roles of the ?eld-dependent mobility and the source and drain series resistances are investigated. For our central-gated device with a 10-nm top GaN channel layer, a 30-nm Al0.3Ga0.7N barrier layer, and a 3-nm Al2O3 gate dielectric, the gate length (LG) as the transition point from the long-channel behavior to the short-channel one is found to be 200 nm. For LG < 200 nm, a linear fT versus LG relation shows up, and notable short-channel effects appear, i.e., the negative shift of the threshold voltage, the increase of the drain-induced barrier lowering, and the almost LG-independent constant maximum transconductance in the saturation region. The degradation of the fT × LG product with the decrease in the aspect ratio between LG and the equivalent gate-channel distance (tt) is shown to be quite small. The LG/tt ratio for 15% degradation of the fT × LG product from its upper limit (19.23 GHz · μm) is 5.5. This small degradation of the frequency characteristics in short-channel devices is attributed to the quite small fringing capacitance of the gate.
关键词： short-channel effect,laterally scaling,N-polar GaN,High-electron mobility transistor (HEMT)
更新于2025-09-12 10:27:22
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Clinical attachment level gain of lasers in scaling and root planing of chronic periodontitis: a network meta-analysis of randomized controlled clinical trials
摘要： The objective of this study was to evaluate the clinical attachment level (CAL) gain of Er:YAG, Er,Cr; YSGG, Nd:YAG; and diode laser (DL) as monotherapy or adjunctive to scaling and root planing (SRP) of chronic periodontitis by network meta-analysis (NMA). Randomized controlled clinical trials (RCTs) about lasers applied in SRP of chronic periodontitis were searched from PubMed, Cochrane Library, Web of Science, Ovid, Science Direct, Wan Fang, and China National Knowledge Infrastructure (CNKI) databases up to September 2018 and from references of selected full-texts and related reviews. Standard mean differences and 95% confidence intervals were counted for CAL gain. The random effects NMA were performed in STATA software. There were 25 RCTs about CAL gain at 3 and/or 6 months after lasers were applied in SRP. No inconsistency was detected. Er:YAG as monotherapy gained significantly more CAL at 3 months than did SRP; no significant differences were detected among other comparisons. In terms of CAL gain at 3 months, the ranking result from best to worst was as follows: Er:YAG as monotherapy, DL adjunctive to SRP, Er:YAG adjunctive to SRP, Er,Cr;YSGG as monotherapy, Nd:YAG adjunctive to SRP, and SRP. In terms of CAL gain at 6 months, the ranking result from best to worst was as follows: DL adjunctive to SRP, Nd:YAG adjunctive to SRP, SRP, Er:YAG adjunctive to SRP, and Er:YAG as monotherapy. Laser-assisted periodontal treatment could be superior to SRP alone and could serve as a good adjunctive treatment tool.
关键词： Network meta-analysis,Lasers,Scaling and root planing,Chronic periodontitis
更新于2025-09-12 10:27:22
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Synergistic Coassembly of Highly Wettable and Uniform Hole‐Extraction Monolayers for Scaling‐up Perovskite Solar Cells
摘要： All organic charge-transporting layer (CTL)-featured perovskite solar cells (PSCs) exhibit distinct advantages, but their scaling-up remains a great challenge because the organic CTLs underneath the perovskite are too thin to achieve large-area homogeneous layers by spin-coating, and their hydrophobic nature further hinders the solution-based fabrication of perovskite layer. Here, an unprecedented anchoring-based coassembly (ACA) strategy is reported that involves a synergistic coadsorption of a hydrophilic ammonium salt CA-Br with hole-transporting triphenylamine derivatives to acquire scalable and wettable organic hole-extraction monolayers for p–i–n structured PSCs. The ACA route not only enables ultrathin organic CTLs with high uniformity but also eliminates the nonwetting problem to facilitate large-area perovskite films with 100% coverage. Moreover, incorporation of CA-Br in the ACA strategy can distinctly guarantee a high quality of electronic connection via the cations’ vacancy passivation. Consequently, a high power-conversion-efficiency (PCE) of 17.49% is achieved for p–i–n structured PSCs (1.02 cm2), and a module with an aperture area of 36 cm2 shows PCE of 12.67%, one of the best scaling-up results among all-organic CTL-based PSCs. This work demonstrates that the ACA strategy can be a promising route to large-area uniform interfacial layers as well as scaling-up of perovskite solar cells.
关键词： hole-extraction monolayer,perovskite solar cells,scaling-up,modules,anchoring-based coassembly strategy
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Design Strategies for Power Scaling of GaSb-Based Superluminescent Diodes for 2 – 3 μm Wavelength Range
摘要： Mid-infrared semiconductor light sources emitting around 2–3 μm wavelength are instrumental for an increasing number of applications, such as molecular spectroscopy, trace-gas sensing, medical diagnostics and eye-safe LIDAR. For example, the monitoring of greenhouse gases (C2H2, CO2, CO and N2O) can be done with higher sensitivity using their molecular fingerprints in this wavelength range [1]. On the other hand, for a wider penetration to applications other important aspects, such as cost, power efficiency, portability and reproducibility are the key enablers. To this end, mid-IR silicon-photonics technology has emerged as a developed platform, yet so far relaying on the use of extended-cavity tunable laser concepts [2]. Alternatively, we have proposed the use of high power, spectrally broadband ridge waveguide (RWG) GaSb-based superluminescent diodes (SLDs) exhibiting single-transverse mode for efficient coupling to silicon photonics waveguide and enabling the development of spectral-programmable broadband light sources [3]. While 2–3 μm GaSb-based laser diodes have shown a good level of performance, yet the development of SLDs devices has seen little progress, owing to the peculiarity of GaSb material system, which is less spread as optoelectronics platform, and physics consideration, for example linked to increased Auger recombination. Most recent developments in the performance of GaSb gain-chips at room temperature (RT) include the demonstration of output powers of up to 60 mW at 1.9 μm [4], 10 mW at 2.25 μm, and 5 mW at 2.38 μm [5] for continuous-wave (CW) operation, and 3.2 mW average power at 2.55 μm [6] for pulse operation. Here we report a comparative study of using novel single- and double-pass SLED designs employing a cavity suppression (CS) element, shown in Fig.1. The active region consists of compressively strained GaInSb/AlGaAsSb double QWs [4]. We operated the devices under CW at RT. The double-pass approach has produced an output power up to 120 mW, which is 100% more than our previous single-pass demonstration. The high power is achieved due to the double-pass light amplification and better material quality. The cavity suppression element enabled high current injection with a broad spectrum having a spectral full width at half maximum (FWHM) of 70 nm and 40 nm for single- and double-pass SLDs, respectively. In conclusion, we reported the highest power GaSb-based SLD demonstrated so far, reaching a power level as high as 120 mW and a spectral bandwidth of 40 nm in a single-transvers mode-operation.
关键词： cavity suppression,single-transverse mode,mid-infrared,power scaling,GaSb-based superluminescent diodes
更新于2025-09-12 10:27:22
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Frequency‐scaled optimized time‐frequency transform for harmonic estimation in photovoltaic‐based microgrid
摘要： Renewable (especially photovoltaic [PV])‐based distributed generations (DGs) integrated via converter stations pose serious challenge against effective monitoring of fundamental and harmonic phasors because of the presence of time‐varying Nth‐order harmonics, which get escalated in terms of voltage flicker, total harmonics distortion profiles with increased penetration level of such renewable sources. The generalized S‐transform (ST) has been used extensively for these nonstationary power signals analysis because it localizes the signal spectrum in time and yields a phase spectrum also for obtaining both amplitude and phase characteristics. However, the transform suffers from large execution time and arbitrary choice of window parameters. The paper, therefore, presents a new approach to extract time‐frequency response (TFR) from a harmonically scaled Fourier kernel ST optimized by metaheuristic firefly algorithm suitable for monitoring of microgrid phasors in real time, which can be ultimately used for effective power management and coordination. This new formulation uses selective frequency scaling to achieve a significant time reduction (within a half cycle of the initiation of the disturbance) in monitoring and tracking time‐varying harmonic disturbances, especially for DG‐integrated operations. Extensive simulation results for monitoring of time‐varying fundamental and harmonics in PV‐based grid‐connected power networks are presented against efficacy measures. Further, to validate in real time, a TMS320 C6713 digital signal processor (DSP) test bench is included in the paper for fundamental and harmonics estimation.
关键词： monitoring,photovoltaic,filtering,nonstationary power signal,harmonics,scaling methods,real‐time S‐transform
更新于2025-09-11 14:15:04
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Effectiveness of Adjunctive Use of Low-Level Laser Therapy and Photodynamic Therapy After Scaling and Root Planing in Patients with Chronic Periodontitis
摘要： The aim of this split-mouth, randomized controlled clinical trial was to evaluate the efficacy of low-level laser therapy (LLLT) and photodynamic therapy (PDT) as an adjunct to scaling and root planing (SRP) in treatment of chronic periodontitis. Each quadrant was categorized into control group (SRP alone; two quadrants per patient), test group 1 (SRP + PDT), and test group 2 (SRP + LLLT. The test groups showed significantly higher reductions in Gingival Index, probing depth, and clinical attachment level as well as reductions in Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans counts at 1-, 3-, 6-, and 9-month follow-ups when compared with the control group.
关键词： photodynamic therapy,chronic periodontitis,low-level laser therapy,scaling and root planing
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Power-Scaling Nonlinear-Mirror Modelocked Thin-Disk Lasers
摘要： High-power ultrafast laser sources constitute a key technology to a wide variety of scientific and industrial applications that benefit from the combination of high average power and sub-ps pulse duration. While coherently combined amplifier systems now deliver kW-level average powers, ultrafast thin-disk lasers (TDLs) remain of considerable interest as compact, low-noise laser sources delivering multi-hundred-Watts with excellent beam quality. These oscillators are usually modelocked using either of two well-established techniques: SESAM or Kerr-lens modelocking (KLM). Recently, we demonstrated the first TDL modelocked using the frequency-doubling nonlinear mirror (NLM). This technique relies on the combination of an intracavity χ(2) crystal used for second-harmonic generation (SHG) and a dichroic output coupler mirror (OC) that is highly reflective for the second harmonic (SH) and partially reflective for the fundamental wave (FW). The NLM device (SHG crystal + dichroic OC) thus provides a saturable reflectivity enabling modelocked operation. Our first NLM-modelocked TDL delivered <30 W with pulse durations >323 fs at a repetition rate of 17.8 MHz. Here we present a power-scaled NLM-modelocked TDL delivering 66 W and 430 fs pulses at 9.3 MHz, and up to 87 W and 586 fs pulses at 8.9 MHz. We thereby improve the output average power by a factor ≈3 and the peak power by a factor ≈5. This corresponds to 3 orders of magnitude more peak power than NLM results based on bulk-crystal lasers. We furthermore identify stable modelocking regimes that avoid Q-switching instabilities.
关键词： modelocking,thin-disk lasers,ultrafast lasers,nonlinear mirror,power scaling
更新于2025-09-11 14:15:04