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High resolution X-ray micro-CT imaging of fibrin scaffold using large area single photon counting detector
摘要： This paper deals with the high resolution X-ray micro-computed tomographical (micro-CT) visualization of a fibrin scaffold intended to be used during medical repairs of various types of human tissue. Due to the cellular nature of scaffolds, it is important to inspect their microstructure in high detail on a volumetric basis. In this work, we demonstrate the micro-CT measurement of a fibrin-based bone scaffold performed using a proprietarily developed tomographical scanner equipped with a large-area imaging device (LAD) composed of 10 × 10 Timepix silicon pixel detectors without any gaps between the individual tiles. The fibrin scaffolds are based on organic materials, which may be reinforced by various additives to improve their mechanical characteristics, and their dimensions are generally very small (i.e. micrometer to millimeter scale). As the organic material used in fibrin scaffolds exhibits very low X-ray attenuation, low-energy X-ray radiation is desirable to achieve sufficient contrast in the projections. Moreover, a high resolution is needed to visualize the fine features in the scaffolds. Here, conventional scintillation detectors suffer two problems that make the aforementioned LAD superior for the imaging of the investigated scaffolds: a wide point-spread function and low sensitivity at low energies. Despite the high LAD sensitivity to low-energy photons, it was necessary to apply several correction procedures to achieve the highest possible resolution. Here, a computational procedure was developed to compensate for the drift of the tube’s focal spot, geometrical imperfections of the LAD detector assembly, and the effects of its border pixels with different responses and sizes. We demonstrate the results on the final reconstructed images based on uncorrected and corrected projections, where we achieved a 1 μm voxel size.
关键词： Computerized Tomography (CT) and Computed Radiography (CR),Inspection with x-rays,Pixelated detectors and associated VLSI electronics
更新于2025-09-04 15:30:14
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H2S and NH3 Detection with Langmuir-Schaefer Monolayer Organic Field-Effect Transistors
摘要： In this work gas sensing properties of Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) have been investigated. The monolayer has been deposited using Langmuir-Schaefer method, which results in a uniform low-defect monolayer with excellent electrical performance, hole mobility up to 7 × 10?2 cm2 V?1 s?1, the threshold voltage around 0 V and on-off ratio of 104. Developed sensors demonstrate a long-term stability of a half-year storage under ambient conditions. Preliminary investigations demonstrated that the LS OFETs give instantaneous response on ammonia and hydrogen sulfide at low concentrations. The results reported open new perspectives for the OFET-based gas-sensing technology.
关键词： OFETs,monolayer,organic electronics,chemical sensing,Langmuir-Schaefer
更新于2025-09-04 15:30:14
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Exploiting In Situ Redox and Diffusion of Molybdenum to Enable Thin-Film Circuitry for Low-Cost Wireless Energy Harvesting
摘要： Direct additive fabrication of thin-film electronics using a high-mobility, wide-bandgap amorphous oxide semiconductor (AOS) can pave the way for integration of efficient power circuits with digital electronics. For power rectifiers, vertical thin-film diodes (V-TFDs) offer superior efficiency and higher frequency operation compared to lateral thin-film transistors (TFTs). However, the AOS V-TFDs reported so far require additional fabrication steps and generally suffer from low voltage handling capability. Here, these challenges are overcome by exploiting in situ reactions of molybdenum (Mo) during the solution-process deposition of amorphous zinc tin oxide film. The oxidation of Mo forms the rectifying contact of the V-TFD, while the simultaneous diffusion of Mo increases the diode’s voltage range of operation. The resulting V-TFDs are demonstrated in a full-wave rectifier for wireless energy harvesting from a commercial radio-frequency identification reader. Finally, by using the same Mo film for V-TFD rectifying contacts and TFT gate electrodes, this process allows simultaneous fabrication of both devices without any additional steps. The integration of TFTs alongside V-TFDs opens a new fabrication route for future low-cost and large-area thin-film circuitry with embedded power management.
关键词： additive fabrication,amorphous oxide semiconductors,thin-film circuitry,large-area electronics,solution process
更新于2025-09-04 15:30:14
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3D stretchable and transparent conductors with controllable strain-distribution based on template-assisted transfer printing
摘要： Although stretchable transparent conductors, stemmed from the strategies of both conductive composite and structural design of non-stretchable conductors, have been extensively studied, these conductors either suffer from a low stretchability or require a complex fabrication process, which drastically limits their practical applications. Here, we propose a novel strategy combining the design of substrates and a simple template-assisted transfer printing process to fabricate 3D transparent conductors. The strategy not only eliminates the complex and costly fabrication processes, but it also endows conductors with high stretchability and long-term stability thanks to the controllable strain-distribution as well as the seamless connection between the conductor layer and the substrate. These newly-designed 3D conductors achieve a low sheet resistance of 1.0 Ω/sq with a high transmittance of above 85% and remain stable without obvious resistance change during 1000 stretching-relaxation cycles until 60% strain, which are superior to most reported conductors. A large-area stretchable heater based on the 3D conductor realizes the temperature fluctuation below 10% even under a large strain, thus showing huge application prospects in the field of wearable healthcare electronics. The simple solution-processed fabrication method and high performance such as stretchability and low resistance change over large strain range promote the practical applications of these newly-designed 3D conductors.
关键词： 3D substrates,template-assisted transfer printing,solution-processed,wearable electronics,stretchable transparent conductors
更新于2025-09-04 15:30:14
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Design of the readout electronics for the DAMPE Silicon Tracker detector
摘要： The Silicon Tracker (STK) is one of the detectors of the DAMPE satellite used to measure the incidence direction of high energy cosmic rays. It consists of 6 X-Y double layers of silicon micro-strip detectors with 73728 readout channels. It is a great challenge to read out the channels and process the huge volume of data in the harsh environment of space. 1152 Application Specific Integrated Circuits (ASIC) and 384 ADCs are used to read out the detector channels. 192 Tracker Front-end Hybrid (TFH) modules and 8 identical Tracker Readout Board (TRB) modules are designed to control and digitalize the front signals. In this paper, the design of the readout electronics for the STK and its performance are presented in detail.
关键词： silicon strip detector,readout electronics,DAMPE,VA140
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - High Voltage GaN Switch Reliability FIT rates and PPM reliability based on standards from: Joint Electron Device Engineering Council (JEDEC), Automotive Electronics Council (AEC) and German Electrical and Electronic Manufacturers' Association (ZVEI)
摘要： Adoption of any semiconductor technology by the power conversion market requires the understanding of fundamental failure modes, acceleration factors and reliability statistics. This study shows how GaN products from Transphorm can meet this challenge, especially in the critical High Voltage Off State (HVOS) reliability stress test. The anticipated failure rate during a product’s first 10 to 20 years of use is of particular interest as it has direct impact on warranty costs. This market requirement can be addressed by testing to failure statistically significant samples of devices, and analyzing the data with appropriate models. The methods developed for measuring GaN reliability on large samples will be discussed, which are wholly based on existing industrial and automotive standards. The resulting data can be used to supplement qualification testing results when the failure modes and acceleration factors are well understood.
关键词： GaN,FIT,PPM,HEMT,acceleration factor,power electronics,reliability
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Thermal and Thermomechanical Modeling to Design a Gallium Oxide Power Electronics Package
摘要： There is significant interest in the power electronics industry in transitioning from silicon to wide-bandgap devices. Gallium oxide devices have the potential to offer comparable or even superior performance than other wide-bandgap devices, but at a much lower cost. Recent breakthroughs include demonstration of a laboratory-scale gallium oxide transistors and diodes; however, a functional power electronics package for these devices is yet to be developed. In this paper, the research methodology in designing an electronics package for gallium oxide devices is outlined. Finite element-based thermal and thermomechanical modeling simulations were conducted to realize a package design that meets the combined target of minimal thermal resistance and improved reliability. Different package designs that include various material combinations and cooling configurations were explored, and their thermal and thermomechanical performance are reported. Furthermore, the short-circuit withstanding capabilities of gallium oxide devices were studied and compared with silicon carbide.
关键词： gallium oxide,thermal modeling,thermomechanical modeling,finite-element,high-temperature packaging,power electronics,wide-bandgap devices
更新于2025-09-04 15:30:14
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Impact of Low‐Frequency Vibrations on Charge Transport in High‐Mobility Organic Semiconductors
摘要： Despite decades of intensive studies of charge transport in organic semiconductors (OSs), understanding of mechanisms underpinning efficient charge transport in them remains elusive. Recently, it has been suggested that low-frequency (LF) vibrations are a limiting factor of charge transport in high-mobility OSs. Nevertheless, the relationship between the molecular structure, crystal packing, LF vibrations, and charge transport is still obscured. This hinders the focused search of high-mobility OSs so that researchers rely mainly on trial-and-error method. This review presents theoretical and experimental approaches to studying the LF vibrations and their role in charge transport with a focus on recent results. It is anticipated that tight cooperation between experimentalists and theorists will yield an advanced understanding of LF vibrations in OSs and their impact on charge transport. This will guide the design of novel high-mobility organic semiconductors for organic electronics.
关键词： structure–property relationship,organic electronics,Raman spectroscopy,electron–phonon interaction,charge mobility
更新于2025-09-04 15:30:14