Single-chip Device Research Articles

TEMPUS, a Timepix4-based system for the event-based detection of X-rays.

TEMPUS is a new detector system being developed for photon science. It is based on the Timepix4 chip and, thus, it can be operated in two distinct modes: a photon-counting mode, which allows for conventional full-frame readout at rates up to 40 kfps; and an event-driven time-stamping mode, which allows excellent time resolution in the nanosecond regime in measurements with moderate X-ray flux. In this paper, the initial prototype, a single-chip device, is introduced, and the readout system described. Moreover, and in order to evaluate its capabilities, some tests were performed at PETRA III and ESRF for which results are also presented.

Metal-organic framework-based high-performance column chip for micro gas chromatography: hybrid function for simultaneous preconcentration and separation of volatile organic compounds.

Numerous attempts have been made to replace commercial bulky gas chromatography (GC) systems with compact GC systems for monitoring volatile organic compounds in indoor air. However, recently developed compact GC systems are still too bulky in terms of user convenience, portability, and on-site analysis. Hence, an advanced miniaturization of compact GC systems is needed. Importantly, the small and high-performance gas pretreatment chip devices should be developed for compact GC systems. This paper reports the development of a metal-organic framework (MOF)-coated hybrid micro gas chromatography column chip (hybrid GC chip) capable of preconcentration and separation on harmful volatile organic compounds at low-concentration in one single chip device. The hybrid GC chip, 2 cm × 2 cm in size, was fabricated using a microelectromechanical systems process. The synthesized MOF-5 particles were coated on the inner wall of the fabricated hybrid GC chip and acted as an adsorbent and a stationary phase. The developed hybrid GC chip afforded high preconcentration factors with 1033-1237 and high separation resolutions with 3.8-13.3. The developed column showed good performance as a gas preconcentrator and separation column, and is the first device to perform both roles in one single chip device.

OpenPose-Based Yoga Pose Classification Using Convolutional Neural Network

Human action recognition has various implementation, such surveillance system, elders care and construction alert, which arouse lots of interest of research in classification of still image. This paper mainly focusses on detecting the pose of Yoga. Comparing with traditional method using convolutional neural network, which is using original image as input to train the VGG network, extracting the skeleton images and feed them into Mobile net can impressively increase the accuracy. Dataset is collected from Kaggle website which contains five categories of labeled Yoga image. Openpose is an open-source API that can extract the human skeleton structure form the Yoga image based on the pose. With these skeleton image as input, the convolutional neural network will perceive everything important such as pose and angle of joints, rather than irrelevant features such as color and environment. Using Mobile net instead of common method to do classification with VGG, calculation time has been remarkably reduced and size of model is lighter which is able to be apply on single chip device. The result of model is impressive, showing high accuracy in both training data set and testing data set, which means no overfitting problem occurred in the experiment. Model size and demanding of hardware are also acceptable for a common personal computer.

Three-terminal photodetectors based on chemical vapor deposition-grown triangular MoSe2 flakes

Two-dimensional (2D) transition metal dichalcogenides (TMDs) materials play a significant role in the fabrication of nano-scale devices. To construct high-performance devices with rich functions for adaptation to specific applications, a strategy for engineering 2D nanostructures must be developed. In addition, multi-channel devices with superior optoelectronic characteristics have attracted great interest because they can be used in nano-chip systems. Herein, we synthesized high-quality and homogenous MoSe2 flakes with the assistance of sodium hydroxide (NaOH) powder by the chemical vapor deposition (CVD) method. Three-terminal photodetectors were fabricated based on the triangular MoSe2 flakes. A high photoresponse can be achieved from the photodetectors with a photoresponsivity of 1.79 mA·W−1 and a specific detectivity of 13.55 × 109 Jones at a bias voltage of 3 V. The key benefits of this type of multi-terminal photodetectors on regular 2D flakes include their usefulness in detecting high-precision light at different locations on a single-chip device. Therefore, this work provides a facile way to fabricate position detection photodetectors on various 2D materials.

Geo-Referenced Mapping through an Anti-Collision Radar Aboard an Unmanned Aerial System

Unmanned aerial systems (UASs) have enormous potential in many fields of application, especially when used in combination with autonomous guidance. An open challenge for safe autonomous flight is to rely on a mapping system for local positioning and obstacle avoidance. In this article, the authors propose a radar-based mapping system both for obstacle detection and for path planning. The radar equipment used is a single-chip device originally developed for automotive applications that has good resolution in azimuth, but poor resolution in elevation. This limitation can be critical for UAS application, and it must be considered for obstacle-avoidance maneuvers and for autonomous path-planning selection. However, the radar-mapping system proposed in this paper was successfully tested in the following different scenarios: a single metallic target in grass, a vegetated scenario, and in the close proximity of a ruined building.

Labchip-based diagnosis system for on-site application: Sensitive and easy-to-implement detection of single recoverable Cronobacter in infant formula without post-enrichment treatment

Microfluidic labchips have achieved much advancement in the molecular diagnosis of foodborne pathogens. Whereas difficulties in the flow control during the transportation of liquid fluids can occur and should be overcome. Manipulations of reaction temperature and the complex procedures from sample pre-treatment to analysis in a single chip device are major obstacles for the on-site application. Thus, the efficient temperature control of samples without any flow of reaction fluids in microfluidic channels of plastic chip and the simplest protocol omitting post-enrichment processing steps may overcome these limitations represented by the stability and the complexity, respectively. This study aims to develop a novel type of labchip and thermocycler specialized for the gene amplification in microfluidic channels and to evaluate the detectability by sensing the minimum recoverable level of Cronobacter in powdered infant formula (PIF). We developed a thermocycling device accelerating reactions through dual heating-blocks optimized to control temperatures of samples in microfluidic-channels by direct contact with labchip sequentially and repetitively. The structural design of microfluidic channels was to eliminate interference factors associated with the optical detection of fluorescent signals (without distortion due to air bubbles in the reaction chamber). To improve the applicability, a portable device and simplified operation to allow direct loading of samples in the chip without post-enrichment procedures were also adopted. Detection performance was evaluated by a sensitivity/specificity tests using 50 isolates of Cronobacter. Cross-reactivity tests for non-Cronobacter organisms and gDNA [human, raw materials of PIF (cow, soybean)] showed that there was no interference-factor causing false-positive results. In terms of the applied research conducted by using PIF, the enrichment of samples without broth medium (distilled water) displayed outstanding performance and 12 h of incubation facilitated detecting target at concentration as low as 1 CFU/300 g PIF (as initial contamination level) without post-enrichment treatment. Validation of the operation conditions using 30 commercial PIF products was also consistent. The present study presents a novel approach of microfluidic technology with perspective to not only the performance and the practicability [easy-to-implement protocol, portable materials, cost-effectiveness (the use of a miniaturized plastic chip requires a minimum level of materials)] for on-site diagnosis.

Investigation on the Effects of Unbalanced Clamping Force on Multichip Press Pack IGBT Modules

Press-pack packaging technology has been widely used in insulated-gate bipolar transistors for high-voltage and high-power density applications. The effects of unbalanced internal pressure, which occurs frequently within large-scale press-pack modules, remain unclear, and thermal parameters within modules cannot be directly measured due to the pressure-type package structure. Current and temperature distribution within 3300 V/1500 A modules are investigated to determine module reliability characteristics and derive future lifetime models using multiphysics models. Unbalanced clamping force causes extremely uneven temperature stress and electrical stress in spatial distribution. It indicates that partial chips must withstand high stresses that cause the initial fatigue of large-scale press-pack modules. Junction temperature difference reaches up to 53.6 °C among chips at chip surface roughness of $1.27~\mu \text{m}$ . This condition shows that the aging of modules will accelerate at the onset of partial chips degradation. Finite-element modeling and equivalent test are utilized to verify the multiphysics model by using single-chip devices in parallel.

Alternating Current III-Nitride Light-Emitting Diodes With On-Chip Schottky Barrier Diode Rectifiers

We report in this paper the design and fabrication of single-chip alternating current-LEDs (AC-LEDs) by monolithically integrating, for the first time, high-breakdown Schottky barrier diodes (SBDs) and micro-LED arrays using III-nitride LED epi-wafers of standard specs for volume production. A technique of cyclic mixed-etching has been introduced to restore the surface of inductively coupled-plasma (ICP) etching processed gallium nitride to device quality for fabricating high-breakdown Schottky junctions. Proof-of-concept single-chip AC-LED devices and a prototype driver-free white AC-LED lamp were demonstrated, showing high-efficiency LED emission, high chip area utilization efficiency, low power loss of the on-chip SBD bridge rectifier, and good luminous efficacy of the prototype AC-LED lamp. This paper paves the way toward mass-producing reliable and low-cost driver-free AC-LED lamps for solid-state lighting with existing LED manufacturing infrastructures.

Ghost imaging using a large-scale silicon photonic phased array chip.

We experimentally demonstrate the use of a large-scale silicon-photonic optical phased array (OPA) chip as a compact, low-cost, and potentially high-speed light illuminating device for ghost imaging (GI) applications. By driving 128 phase shifters of a newly developed silicon OPA chip using rapidly changing random electrical signals, we successfully retrieve a slit pattern with over 90 resolvable points in one dimension. We then demonstrate 2D imaging capability by sweeping the wavelength. With the potential of integrating high-speed phase modulators, tunable lasers, grating couplers, and CMOS driver circuit on the same silicon platform, this work paves the way towards realizing ultrahigh-speed and low-cost single-chip GI devices.

A Highly-Efficient Single Segment White Random Laser.

Production of multicolor or multiple wavelength lasers over the full visible-color spectrum from a single chip device has widespread applications, such as superbright solid-state lighting, color laser displays, light-based version of Wi-Fi (Li-Fi), and bioimaging, etc. However, designing such lasing devices remains a challenging issue owing to the material requirements for producing multicolor emissions and sophisticated design for producing laser action. Here we demonstrate a simple design and highly efficient single segment white random laser based on solution-processed NaYF4:Yb/Er/Tm@NaYF4:Eu core-shell nanoparticles assisted by Au/MoO3 multilayer hyperbolic meta-materials. The multicolor lasing emitted from core-shell nanoparticles covering the red, green, and blue, simultaneously, can be greatly enhanced by the high photonic density of states with a suitable design of hyperbolic meta-materials, which enables decreasing the energy consumption of photon propagation. As a result, the energy upconversion emission is enhanced by ∼50 times with a drastic reduction of the lasing threshold. The multiple scatterings arising from the inherent nature of the disordered nanoparticle matrix provide a convenient way for the formation of closed feedback loops, which is beneficial for the coherent laser action. The experimental results were supported by the electromagnetic simulations derived from the finite-difference time-domain (FDTD) method. The approach shown here can greatly simplify the design of laser structures with color-tunable emissions, which can be extended to many other material systems. Together with the characteristics of angle free laser action, our device provides a promising solution toward the realization of many laser-based practical applications.

A New Microchip Design. A Versatile Combination of Electromembrane Extraction and Liquid-Phase Microextraction in a Single Chip Device.

For the first time, a novel and versatile microfluidic device was developed to achieve the possibility of combining different extraction principles using a miniaturized approach for the extraction of different classes of analytes. This novel microchip is composed of a sandwich of three poly(methyl methacrylate) (PMMA) layers. Four channels allowed the combination of electromembrane extraction (EME) and liquid-phase microextraction (LPME) in three different ways: (I) EME and LPME, (II) EME and EME, or (III) LPME and LPME. The microchip can be used either (a) using a common acceptor phase (for both extractions) for the simultaneous extraction of drugs from different nature in a single step, or (b) a common sample solution (for both extractions) and two acceptor solutions for simultaneous drug separation. In this work, the performance of this novel microchip was demonstrated by simultaneous integration of EME and LPME using a common acceptor phase for both extractions. This configuration reduces the time of analysis allowing direct analysis in a single chip. The microchip was tested for extracting two different classes of analytes: five fluoroquinolones and four parabens as model analytes. All effective variables were optimized for EME and LPME. Under the optimized conditions, the reusable microchip enables simultaneous μ-EME/LPME with extraction efficiencies over 77% in only 8 min extraction and sample volume consumption lower than 40 μL. The optimized procedure was successfully applied to urine samples obtaining recoveries over 90% for all analytes.

CMOS-based opto-electronic neural interface devices for optogenetics.

CMOS-based opto-electronic neural interface devices are presented. The devices are designed with target application of in vitro and in vivo optogenetics. Two types of the opto-electronic neural interface devices are presented. One is single-chip type device for on-chip optogenetics, and the other is multi-chip type device with flexibility and wide-area coverage for in vivo optogenetics on brain. Design, packaging and functional evaluations are presented.

A Microfluidic Device with Continuous Ligand Gradients in Supported Lipid Bilayers to Probe Effects of Ligand Surface Density and Solution Shear Stress on Pathogen Adhesion

Studying binding interactions involving living cells requires a platform that carefully mimics the physiological parameters that govern these phenomena. Very often the amount of ligands that receptors can bind affect overall binding strength as is the case in cell adhesion. In addition, the physical environment can strongly influence these processes. This is exemplified by the effect of shear stress in catch‐bond‐mediated binding of bacteria. Traditional analysis techniques do not allow to probe these factors simultaneously. To this end, continuous ligand gradients in locked‐in supported lipid bilayers (SLBs) are prepared in a microfluidic device to control fluid flow. This platform allows for one‐pot characterization of cell surface binding events and 1) the effect of ligand density and 2) shear stress, simultaneously. The model interaction between the FimH receptor found on Escherichia coli and mannose found on the mammalian cell membrane is used to evaluate the platform. Using a single chip, specific E. coli ORN 178 adhesion (K d of 0.9 × 10−21 m), detachment and displacement are shown to depend on the mannose‐density and shear stress. For the first time, these effects are studied in a single chip device with high quality. This chip provides entry to further our understanding of other cell–cell interactions.

Low Reverse Recovery Charge 30 V Power MOSFET With Double Epi Structure for DC–DC Converters

Low reverse recovery charge solutions are proposed for 30 V power MOSFETs featuring a double epi structure. The parallel connection of a MOSFET and a Schottky barrier diode (SBD) is used to reduce the recovery charge. The breakdown voltage of the SBD area must be enhanced in order to integrate the MOSFET and the SBD on a single chip. Thus, we studied two types of devices using a double epi structure for enhancing the breakdown voltage of the SBD area. One is an integrated single-chip device and the other is an integrated unit cell device. The integrated unit cell device exhibited lower reverse recovery currents than the integrated single-chip device did during the simulations that were conducted. However, the loss calculation of the integrated unit cell device resulted in an increase in loss because of the diode characteristics needed for the greater barrier height of the p−-layer. Therefore, the integrated single-chip device was experimentally investigated. As a result, the surge voltage of the device was reduced by 58%, which enabled for the use of a lower voltage device and a reduction in the device loss.

Fabrication and characterization of high-efficiency double-sided blazed x-ray optics.

The focusing efficiency of conventional diffractive x-ray lenses is fundamentally limited due to their symmetric binary structures and the corresponding symmetry of their focusing and defocusing diffraction orders. Fresnel zone plates with asymmetric structure profiles can break this limitation; yet existing implementations compromise either on resolution, ease of use, or stability. We present a new way for the fabrication of such blazed lenses by patterning two complementary binary Fresnel zone plates on the front and back sides of the same membrane chip to provide a compact, inherently stable, single-chip device. The presented blazed double-sided zone plates with 200 nm smallest half-pitch provide up to 54.7% focusing efficiency at 6.2 keV, which is clearly beyond the value obtainable by their binary counterparts.

An optofluidic system with volume measurement and surface plasmon resonance sensor for continuous glucose monitoring

The traditional technology of glucose monitoring is painful and invasive because of the frequent blood collection. Nowadays, the enzyme electrode sensor is mainly used for continuous glucose monitoring in clinic, but it has inherent disadvantages of significant signal drift of current due to bioelectricity in body and the missing of hypoglycemia resulting from the irreversible consumption of glucose at the process of enzyme catalytic reaction. Interstitial fluid (ISF) transdermal extraction can be nearly unsensible which effectively reduces the pain caused by invasive detection so that it may provide a new way to monitor glucose. MEMS technology has been used to produce devices for transdermal ISF extraction, but there is a lack of on-chip ISF volume measurement capabilities, which are required to compensate skin permeability variations. This paper presents a lab-on-a-chip system for ISF transdermal extraction, ISF volume measurement, and optical glucose sensing towards the application of continuous glucose monitoring. The device significantly incorporates a MEMS volume sensor, which measures extracted ISF volume via conductance monitoring, and integrates a fiber-optic surface plasmon resonance sensor to measure glucose concentration in microchannel. The fiber-based technique provides an excellent approach to overcome the above two drawbacks of the enzyme electrode based glucose sensing. Six different volumes were tested, and the standard deviation of every sample is less than 0.05 μl, The resonance wavelength moves from 549.081 nm to 592.914 nm while the concentration ranges from 0 to 200 mg/dl. The feasibility of the single-chip device for accurate and continuous monitoring of subcutaneous ISF glucose concentrations is verified.

Gas Analysis System on Chip With Integrated Diverse Nanomaterial Sensor Array

A polydimethylsiloxane micromolded separation column is presented with monolithically integrated gas injection, temperature control, and a nanomaterial chemiresistor array for multiparametric gas detection in complex mixtures on a unique single chip platform. Sensor arrays are made of carbon nanotubes, vanadium oxide, and reduced graphene oxide nanomaterials. The functionality of a micromolded gas separation device as opposed to the conventional etched silicon μGC column opens the door to disposable, easily manufactured, stand-alone gas chromatography for clinical diagnostics or remote fieldwork. Combining separation column with a diverse nanomaterial sensor array provides multiparametric detection of gases in a single chip device. The device has the dimensions of a glass slide while drawing <;2 W of power and capable of separation and detection of gases verified using a standard analytical mixture of aliphatic compounds.

A double-sided, single-chip integration scheme using through-silicon-via for neural sensing applications.

We present a new double-sided, single-chip monolithic integration scheme to integrate the CMOS circuits and MEMS structures by using through-silicon-via (TSV). Neural sensing applications were chosen as the implementation example. The proposed heterogeneous device integrates standard 0.18 μm CMOS technology, TSV and neural probe array into a compact single chip device. The neural probe array on the back-side of the chip is connected to the CMOS circuits on the front-side of the chip by using low-parasitic TSVs through the chip. Successful fabrication results and detailed characterization demonstrate the feasibility and performance of the neural probe array, TSV and readout circuitry. The fabricated device is 5 × 5 mm(2) in area, with 16 channels of 150 μm-in-length neural probe array on the back-side, 200 μm-deep TSV through the chip and CMOS circuits on the front-side. Each channel consists of a 5 × 6 probe array, 3 × 14 TSV array and a differential-difference amplifier (DDA) based analog front-end circuitry with 1.8 V supply, 21.88 μW power consumption, 108 dB CMRR and 2.56 μVrms input referred noise. In-vivo long term implantation demonstrated the feasibility of presented integration scheme after 7 and 58 days of implantation. We expect the conceptual realization can be extended for higher density recording array by using the proposed method.

Wavelength-Switchable Lasing From a Polymer Single Chip Device Codoped With Organic Dyes

We demonstrated a wavelength-switchable lasing operation in a single-chip polymer waveguide device. This device has a single active layer codoped with two organic dyes, Stilbene 420 and Rhodamine B, and is equipped with a distributed-feedback resonator by a single-pitched grating. Since there is no significant spectral overlap between the emission band of Stilbene 420 and the absorption band of Rhodamine B, both of these dyes could be simultaneously activated as the optical gain media in the active layer. Under the optical pumping, bistable blue and red lasing emissions were obtained, which were attributed to the third-order distributed-feedback oscillation for the Stilbene 420 emission and the second-order distributed-feedback oscillation for the Rhodamine B emission, respectively. These lasing modes could be easily switched by changing the pumping wavelength.

The Electronic Counting System Design Based on Single Chip Microcomputer

Posture in the drug particles falling was changed through the interaction of rotating plate , apron and the centrifugal force of the plate, in order to achieve the tablet as a single order fall, to avoid duplication of drug particles. Counting drug granules using the photoelectric effect, received signals through the data acquisition circuit. When the count was the same as the value set in advance, the relay acted, and the flap opened, tipped by the alarm circuit for changing bottles. This single-chip counting device in factory production lines for product statistics, has irreplaceable advantages compared to other counting devices.