bluuebunny/crossref_metadata_2025 huggingface dataset:
Reversible Total Ionizing Dose Effects in NiO/Ga2O3 Heterojunction Rectifiers
Authors: Li Jian-Sian , Chiang Chao-Ching , Xia Xinyi , Stepanoff Sergei , Haque Amanul , Wolfe Douglas , Ren Fan , Pearton Stephen J
Published: September 2023

NiO/Ga2O3 heterojunction rectifiers were exposed to 1Mrad fluences of Co-60 g-rays either with or without reverse biases. While there is small component of Compton electrons (600 keV), generated via the interaction of 1.17 and 1.33 MeV gamma-photons with the semiconductor, which in turn can lead to displacement damage, most of the energy is lost to ionization. The effect of the exposure to radiation is a 1000x reduction in forward current and 100x increase in reverse current in the rectifiers, which is independent of whether the devices were biased during this step. The on-off ratio is also reduced by almost 5 orders of magnitude. There is a slight reduction in carrier concentration in the Ga2O3 drift region, with an effective carrier removal rate of < 4 cm-1. The changes in electrical characteristics are reversible by application of short forward current pulses during repeated measurement of the current-voltage characteristics at room temperature. There are no permanent total ionizing dose effects present in the rectifiers to 1 Mad fluences, which along with their resistance to displacement damage effects indicate these devices may be well-suited to harsh terrestrial and space radiation applications if appropriate bias sequences are implemented to reverse the radiation-induced changes.

Figure 1
Analysis and Classification of Charge Trapping States in β-Ga2O3 Mosfets Using I-V and C-V in Dark and Illumination Conditions
Authors: Maimon Ory , Moser Neil , Chamria Div , Liddy Kyle , Green Andrew , Chabak Kelson , Pookpanratana Sujitra , Li Qiliang
Published: September 2023

Beta-gallium oxide (β-Ga2O3) is a promising ultra-wide bandgap semiconductor for high power applications. Its breakdown electric field of 8 MV cm-1, a Baliga figure of merit 3-10 times larger than that of SiC and GaN, and the ability to be grown from the melt make it highly attractive for the semiconductor industry. Significant improvements have been made in β-Ga2O3 device performance for both high power and high frequency operation. Currently, aluminum oxide (Al2O3) is the preferred gate dielectric for β-Ga2O3 transistors due to its electron and hole barriers, and similar atomic structure. Process optimizations to improve the interface quality has been explored by chemical treatments1 to the β-Ga2O3 surface before dielectric deposition, during the deposition of Al2O3, and with post-deposition annealing. Therefore, there is a desire to understand and classify defects at and near the Al2O3/β-Ga2O3 interface. Here, we report on a study of the Al2O3/β-Ga2O3 interface and border traps in planar depletion-mode β-Ga2O3 MOSFETs using DC I-V and C-V measurements in dark and under illumination with wavelengths from 730 nm (1.7 eV) to 230 nm (5.4 eV).

The MOSFETs are fabricated on a 50 nm Si-doped epitaxial layer with a target doping concentration of 2.4 x 1018 cm-3 grown on a (010) semi-insulating β-Ga2O3 substrate. A Ti/Al/Ni/Au metal stack is deposited and annealed to form the Ohmic contacts. Plasma-assisted atomic layer deposition (PE-ALD) is used to deposit the 20 nm Al2O3 gate dielectric. The fabricated transistor structures have a LG of 1.94 µm, LS of 0.5 µm, and LD varying from 0.5 µm, 5.5 µm, and 10.5 µm. Measurements were performed at room temperature. Most FETs exhibited a threshold voltage of approximately -4 V, high linearity, and ION/IOFF ratios between 107 – 109.

Using the conductance method, we extract an interface trap state density, Dit, of 3 x 1011 eV-1 cm-2 up to 0.44 eV below the conduction band. Illumination is used to obtain deep trap concentration and behavior. We observe little to no change in IV and CV curves for wavelengths above 365 nm but see a significant voltage shift in the CV curves for illumination wavelengths between 365 nm (3.4 eV) to 230 nm (5.4 eV), indicating significant activated traps from 3.4 eV below the conduction band. We will present the analysis of photo-assisted CV and stress-CV curves at various wavelengths to obtain densities of fixed, fast, and slow trap states and discuss their impact on device performance.
(Invited) Epitaxial Growth and Characterization of Ga2O3 Polymorphs
Authors: Porter Lisa M , Jiang Kunyao , Tang Jingyu , Cabral Matthew J. , House Stephen D , Yang Judith C , Davis Robert F.
Published: September 2023

Gallium oxide (Ga2O3) is an ultra-wide band gap semiconductor with extraordinary potential for high-power, high-frequency, and high-temperature electronics and UV optoelectronics. The existence of stable and metastable phases, or polymorphs, of Ga2O3 presents challenges and opportunities for future device development. β-Ga2O3 is the thermodynamically stable phase and occurs in melt-grown, single-crystal substrates. The metastable phases, which have been demonstrated in pure- or mixed-phase form in epitaxial films, also possess ultra-wide bandgaps. Intriguing properties, such as ferromagnetism and ferro- and/or piezoelectricity, have been reported for certain phases and could enable new types of devices based on Ga2O3. Controlled growth of different Ga2O3 polymorphs could also lead to structurally-matched alloys, e.g., with In2O3 (Eg = 3.7 eV) and Al2O3 (Eg = 8.8 eV), to modulate bandgaps. In this presentation an overview of the stable and metastable Ga2O3 phases in terms of properties and growth methods will be given. We will present results from chemical vapor deposition, highlighting how certain conditions (e.g., temperature, growth rate, substrate, and impurity content) can affect the resulting polymorph(s). Characterization of phase composition, microstructure, and morphology using x-ray diffraction, scanning electron microscopy, and scanning transmission electron microscopy will be shown for each type of film.
(Invited) NiO/ β-(Al
x
Ga1-x
)2O3 /Ga2O3 Heterojunction Lateral Rectifiers with Reverse Breakdown Voltage > 7kV
Authors: Wan Hsiao-Hsuan , Li Jian-Sian , Chiang Chao-Ching , Xia Xinyi , Ren Fan , Masten Hannah , Lundh James Spencer , Spencer Joseph , Alema Fikadu , Osinsky Andrei , Jacobs Alan G. , Hobart Karl D. , Tadjer Marko J. , Pearton Stephen J
Published: September 2023

There is significant recent interest in development of Ga2O3 power devices due to their capability for high temperature operation, reduced on-state and switching losses due to lower on-resistance for high voltage devices, and potentially higher frequency switching capability. These are targeted for renewable energy transmission systems, electric vehicle (EV) traction inverter and motor control systems, fast charging stations and more electric aircraft. Since the efficiency of EV powertrain inverters is partially determined by the efficiency of the switching transistors, it is of interest to examine ultra-wide-bandgap semiconductor electronics. The successful development of these power transistors is expected to significantly increase the longevity of a battery charge and the resultant cost of an EV.

In this work, NiO/ β-(Al
x
Ga1-x
)2O3 /Ga2O3 heterojunction lateral geometry rectifiers with diameter 50-100 µm exhibited maximum reverse breakdown voltages >7kV, showing the advantage of increasing the bandgap using the β-(Al
x
Ga1-x
)2O3 alloy. This Si-doped alloy layer was grown by Metal Organic Chemical Vapor Deposition with an Al composition of ~20%. On state resistances were in the range 50-2180 Ω.cm2, leading to power figures-of-merit up to 0.72 MW.cm-2. The forward turn-on voltage was in the range 2.3-2.5 V, with maximum on/off ratios >700 when switching from 5V forward to reverse biases up to -100V. Transmission line measurements showed the specific contact resistance was 0.12 Ω.cm2. The breakdown voltage is among the highest reported for any lateral geometry Ga2O3-based device.

Figure 1
Biaxial, Hybrid Plastic-Elastic Relaxation in Micropatterned Semipolar InGaN Buffer Layers Improves Quality of Templated Quantum Well Emitters
Authors: Shapturenka Pavel , Pynn Christopher D. , Chan Lesley , Gordon Michael J. , DenBaars Steven P.
Published: September 2023

Despite significant progress and multiple creative approaches taken toward the realization of long-wavelength III-nitride based light emitters over the past decade, high double-digit external quantum efficiencies remain elusive for GaN/InGaN based devices for wavelengths longer than 525 nm. This stems from the large mismatch between the GaN and InGaN lattice that manifests in deleterious crystal strain gradients, degrades surface growth morphology, and introduces diverse and potent nonradiative defects.

A promising route to mitigation of strain-based effects is templating epitaxial growth on relaxed InGaN epilayers; in particular, a known and controllable platform for uniaxial strain relaxation is the creation of 1-D misfit dislocation arrays at semipolar GaN/InGaN heterointerfaces. Leveraging work by Hardy et al. on achieving >200 nm thick, partially relaxed semipolar InGaN layers [1] and precise determination of InGaN epilayer strain state and composition by Young et al. [2], we explore the potential for 2-D buffer layer relaxation in (11-22) InGaN layers via micron- and sub-micron patterning. Cathodoluminescence microscopy and x-ray diffraction indicated significant increases in biaxial epilayer relaxation with increased pillar aspect ratio; quantum wells deposited atop these relaxed InGaN buffers showed dramatic threading dislocation reduction, luminescence and morphology improvements, and evidence of improved indium incorporation relative to planar samples at nominally identical growth conditions.

[1] Hardy, M.T., Young, E.C., Hsu, P.S., Haeger, D.A., Koslow, I.L., Nakamura, S., DenBaars, S.P., Speck, J.S. Suppression of m-plane and c-plane slip through Si and Mg doping in partially relaxed (20-21) InGaN/GaN heterostructures. Appl. Phys. Lett.
101, 132102 (2012).

[2] Young, E. C., Romanov, A.E., Speck, J.S., Determination of composition and lattice relaxation in semipolar ternary (In,Al,Ga)N strained layers from symmetric x-ray diffraction measurements. Appl. Phys. Express. 4, 061001 (2011).
A Capacitor-Based Synaptic Device with IGZO Access Transistors for Neuromorphic Computing
Authors: Won Jongun , Roh Youngchae , Kang Minseung , Park Yeaji , Kang Jaehyeon , Seo Hyeongjun , Joe Changhoon , Kim SangBum
Published: September 2023

IGZO TFT has extremely low leakage current characteristics compared to Si-CMOS, so it can be applied not only to displays but also to various research fields. One of the important applications using IGZO TFT is analog-based synaptic device for the efficient implementation for deep learning. The application of IGZO TFT to a synaptic device was more widely studied after a synaptic device based on Si-CMOS and capacitor was devised in 2017(1). Since insufficient retention time was a remaining problem in Si-CMOS and capacitor-based storage synaptic devices, the combination of IGZO TFT with low leakage current and capacitor was a very attractive solution. However, because the viable p-type metal oxide TFT does not exist, linearity and symmetry of weight update, a major requirement of on-chip trainable synaptic devices, has been difficult to achieve. In our research, for the first time, we obtained linear and symmetric weight update characteristics by combining an IGZO TFT and a capacitor.

In addition, we verified the leakage characteristics of IGZO TFT and the retention characteristics of synaptic devices, which are the most important characteristics. Through the single TFT measurement result, we were able to obtain a leakage current per channel width 1µm of 10-17A, which is much smaller than the Si transistor. Lower leakage current will lead to better retention characteristics than conventional Si-CMOS-based devices, which will result in higher accuracy in deep neural network training. Based on the published results, the IGZO TFT synapse is projected to be able to achieve the retention time of ~4×109s using only 10fF capcacitor.

Another important factor that affects deep neural network training is cell-to-cell and device-to-device variation. As opposed to capacitive synaptic devices, resistive synaptic devices such as Resistive RAM and Phase Change Memory suffer from large device variation. We also verified the device variation characteristics, which are advantages of charge storage devices based on transistors and capacitors. The variation characteristics of the device were evaluated through the ΔG+3σ/ΔG-3σ(%) formula and an excellent result of ~200% was obtained.

In our research, we verified the main characteristics for on-chip training of synaptic devices based on IGZO TFT and capacitor: linearity and symmetry of weight update, retention characteristics and variation characteristics. The remarkable characteristics of synaptic devices based on IGZO TFT and capacitor will be a good candidate for on-chip training.

1. S. Kim, T. Gokmen, H. M. Lee, and W. E. Haensch, Midwest Symp. Circuits Syst., 2017-Augus, 422–425 (2017).

Acknowledgements

This research was supported by National R&D Program through the National Research Foundation of Korea(NRF) funded by Ministry of Science and ICT(NRF-2020M3F3A2A01081240)
Synthesis, Gas Sensing and Photocatalytic Properties of Manganese-Doped and Potassium-Doped Hexagonal Tungsten Trioxide Nanowires
Authors: Chen Pin-Ru , Fu Hsuan-Wei , Yang Shu-Meng , Lu Kuo-Chang
Published: September 2023

On account of its unique and variable lattice structure and stoichiometric ratio, tungsten oxide is suitable for material modification; for example, doping is expected to improve its catalytic properties. However, most of the doping experiments are conducted by hydrothermal or multi-step synthesis, which is not only time-consuming but also prone to solvent contamination, having little room for mass production. Here, without a catalyst, we report the formation of high-crystallinity manganese-doped and potassium-doped tungsten oxide nanowires through chemical vapor deposition with interesting characterization, photocatalytic, and gas sensing properties. The structure and composition of the nanowires were characterized by transmission electron microscopy and energy-dispersive spectroscopy, while the morphology and chemical valence were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. Electrical measurements show that the single nanowires doped with manganese and potassium had resistivities of 1.81 × 10−5 Ω·m and 1.93 × 10−5 Ω·m, respectively. The doping contributed to the phase transition from monoclinic to metastable hexagonal for the tungsten oxide nanowires, the structure of which is known for its hexagonal electron channels. The hexagonal structure provided efficient charge transfer and enhanced the catalytic efficiency of the tungsten oxide nanowires, resulting in a catalytic efficiency of 98.5% for the manganese-doped tungsten oxide nanowires and 97.73% for the potassium-doped tungsten oxide nanowires after four hours of degradation of methylene blue. Additionally, the gas sensing response for 20 ppm of ethanol showed a positive dependence of doping with the manganese-doped and potassium-doped responses being 14.4% and 29.7%, respectively, higher than the pure response at 250 °C. The manganese-doped and potassium-doped tungsten oxide nanowires are attractive candidates in gas sensing, photocatalytic, and energy storage applications, including water splitting, photochromism, and rechargeable batteries.
(Invited) advantageous Utilization of Triboelectricity Based Electric Signals for Energy Harvesting and Self-Powered Sensing
Authors: CHOI Dongwhi
Published: September 2023

Triboelectric signal generation, which is originated from sequential contact and separation of two different materials including liquid, is highlighted as a novel mechanism for development of various types of energy harvesters as well as self-powered sensors. Unlike most of the regarding research as materials and chemistry oriented approaches, the role of the classical mechanics in aforementioned triboelectric signal generation is introduced. By adopting the ordinary power transmission unit into the triboelectricity based energy harvester, called triboelectric nanogenerator (TENG), the output performance can be significantly increased and such remarkable increase allows us to use the triboelectric signal generation mechanism more practically. As one of the representative examples, the effective biomechanical energy harvesting via triboelectric signal generation is introduced. Along with it, the advantageous effect of the triboelectric signal generation on the operation of the classical mechanical elements, which are frequently employed for direct power transmission, is proposed. In this regard, the self-triggered mechanical sensors, which enable us to inform various characteristics of the machine components, are proposed. Since the electric signal can be generated without any other external power sources, the present sensor can be considered as self-triggered. Gear and brake are one of the most ordinary and effective components for transmitting mechanical power as a core component of machines. Given that the operation of the gear and brake in power transmission is based on sequential contact and separation between two separated components, the simple modification of the outermost surface of the conventional machine components enables us to spontaneously generate triboelectric signal during ordinary power transmission. The present approach to utilize state-of-the-art triboelectric signal generating mechanism could open new application fields by converging it with the classical mechanics.
Liquid-Liquid Triboelectric Nanogenerators Based on Bionic Slippery Lubricant-Infused Porous Surfaces
Authors: Yeh Hsuan-Yu , Lin Zong-Hong , Chen Po-Yu
Published: September 2023

In the era of high energy dependence, self-powered smart devices have been widely used in the energy field, especially the continuous long-term operation in harsh environments is the biggest challenge at present. In the past few years, the innovation of Triboelectric nanogenerator (TENG) can effectively convert the kinetic energy of ocean waves and rain into electricity. However, this type of equipment encounters a bottleneck in practical applications, that is, the equipment is exposed to harsh environments for a long time, which will cause damage or aging due to inevitable physical and chemical effects, resulting in reduced power output. To overcome this difficulty, we propose an innovative liquid-liquid TENG (L-L TENG) integrated with slippery lubricant-infused porous surfaces (SLIPS), which is called SLIPS-TENG. Inspired by nepenthes, we use Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) imitates its unique structure as the base layer through electrospinning, and inject silicon oil (SO) to form a uniform, defect-free and slippery hydrophobic coating on the base layer to prevent liquids from adhering to the surface of the TENG device. The results show that the liquids on SLIPS-TENG show lower contact hysteresis than TENG fabricated with only hydrophobic surface, and the fast sliding enables efficient charge transfer during the drop process. In addition, combined with the versatility of SLIPS-TENG, its self-healing and self-cleaning capabilities enable it to continue operating stably in harsh environments or at extreme low temperatures.
(Invited) harnessing the Barrier Oxide Layer of Nanoporous Anodic Alumina for Iontronic Sensing
Authors: Santos Abel , Law Cheryl Suwen , Wang Juan
Published: September 2023

The hemispherical barrier oxide layer (BOL) closing the tips of hexagonally distributed arrays of cylindrical nanochannels in nanoporous anodic alumina (NAA) membranes is structurally engineered by anodizing aluminum substrates in three distinct acid electrolytes at their corresponding self-ordering anodizing potentials. These nanochannels display a characteristic ionic current rectification (ICR) signal between high and low ionic conduction states, which is determined by the thickness and chemical composition of the BOL, and the pH of the ionic electrolyte solution. Rectification efficiency of ionic current associated with the flow of ions across the anodic BOL increases with its thickness, under optimal pH conditions. The inner surface of nanopores in NAA membranes was chemically modified with thiol-terminated functional molecules. The resultant NAA-based iontronic system provides a model platform to selectively detect gold metal ions (Au3+) by harnessing dynamic ICR signal shifts as the core sensing principle. The sensitivity of the system is proportional to the thickness of the barrier oxide layer, where NAA membranes produced in phosphoric acid at 195 V with a BOL thickness of 232 ± 6 nm achieve the highest sensitivity and low limit of detection in the sub-picomolar range. This study provides exciting opportunities to engineer NAA structures with tailorable ICR signals for specific applications across iontronic sensing and other nanofluidic disciplines.

Figure 1
Electrical Stimulation with Multi-Layer Stacked Electret Based on Superposition Effect for Inhibition of Scar Formation
Authors: Cho Sumin , Kim Sung-Won , Lee Donghan , Bhang Suk Ho , CHOI Dongwhi
Published: September 2023

Skin protects the organs from the external environment as an outermost barrier. In this regard, to maintain human health upon injury, it is significantly necessary to cure rapid and scarless wound healing. Electrical stimulation is recently getting great attention in skin tissue engineering for manipulating wound healing. However, the complexity of equipment to apply appropriate electrical stimulation remains an ongoing challenge. Here, we proposed a scarless wound healing strategy to apply electrical stimulation with the multi-stacked electret (MS-electret), which can easily control the intensity of electrostatic fields (EFs) by stacking electret layers. This strategy is successfully demonstrated through in vitro and in vivo experiments, as a result, inhibiting the activity of myofibroblasts are crucial to achieve sound wound regenerative outcome. Therefore, the MS-electret plays a role as restrict scar formation. Consequently, these findings presented that the usefulness of the MS-electret is outstanding candidate for effective scar-less wound healing with a battery-free, physiological electrical microenvironment, and non-invasive treatment enabling it to prevent external infection.
(Invited) novel Functional π-Conjugated Materials for Photonics, Electronics, and Sensing
Authors: Sonar Prashant Murlidhar
Published: September 2023

Next generation active electronic materials used in devices are undergoing continual improvements to generate devices that are high performance, lighter, flexible, stretchable, and more energy efficient with lower cost. Carbon based novel solution processable π-functional conjugated materials are the focus of intense academic and industrial research since they are important class of soft materials for large area electronics including transistors, displays, sensors and light harvesting devices. The active organic semiconducting materials are emerging due to their tunable light absorption/emission, interesting charge transport properties, relatively adequate HOMO-LUMO energies and ink formulation capability.

In my talk, I will explain the various classes of conjugated carbon-based materials either as polymers, small molecules or quantum dots prepared via chemically and electrochemically using various novel aromatic conjugated building blocks. In this presentation, the design, synthesis, optoelectronic properties, and device performance of novel advanced materials for field effect/electrochemical transistors, perovskite solar cells, light emitting diodes, optical sensors and various sensing devices will be discussed. Such materials and devices have great potential in future electronics, energy, health, and environmental monitoring.

Figure 1
(Invited) 3D-Printed Epidermal Microfluidic Systems for the Collection and Analysis of Sweat
Authors: Ray Tyler R
Published: September 2023

An emerging class of wearable devices integrates microfluidic lab-on-chip designs with low-modulus materials, colorimetric assays, and electrochemical sensors to support the real-time, non-invasive analysis of sweat. Such skin-interfaced microfluidic systems offer powerful capabilities for personalized assessment of health, nutrition, and wellness through the non-invasive, real-time analysis of sweat. Initially simple systems of microfluidic channels, current devices comprise sophisticated networks channels, valves, and reservoirs with some embodiments employing multilayer design strategies. While these platforms exhibit powerful analytical capabilities, device fabrication requires time, labor, and resource-intensive cleanroom processing, which restricts the device design space (2D) and elongates the development time. Additive manufacturing processes, particularly stereolithography (SLA)-based printing, offer powerful pathways for overcoming these limitations by providing significant reductions in prototype development cost and cycle time while substantially expanding device capabilities with fully 3D device designs. Here, we present a simplified 3D-printing prototyping process to fabricate flexible, stretchable, epidermal microfluidic devices (‘3D-epifluidics’). Reducing fabrication time to [O]min, this approach enables the integration of spatially-engineered features including 3D-structured passive capillary valves, monolithic channels, and reservoirs with spatially-graded geometries. With geometric features comparable to established epifluidic devices (channels >50 μm), benchtop and on-body testing validate the performance of 3D-epifluidic devices.
(Invited) Intelligent Fiber Electronics for Textile Computation
Authors: Yan Wei
Published: September 2023

Textiles are an indispensable part of our everyday life. They provide us with protection, offer privacy, and form an intimate expression of ourselves through their aesthetics. Imparting functionality at the fiber level represents an intriguing path toward innovative textiles with a hitherto unparalleled functionality and value. The integration of a variety of electronic and optoelectronic materials within thermally-drawn fibers has enabled fiber electronics. A new generation of textiles that can see, hear and speak, sense, communicate, harvest and store energy, as well as store and process data is thus emerging, setting a stage for textiles to be the next frontier in computation. This talk will feature fiber electronics enabled intelligent textiles which is becoming a sophisticated platform delivering value-added services for our society.

Figure 1. Thermally drawn fibers that integrate chips, circuits, semiconductors, metals, dielectrics, composites, etc. can be directly woven into fabrics enabling a multitude of functionalities [1, 2].

[1] Wei Yan, Grace Noel, Gabriel Loke, Elizabeth Meiklejohn, Tural Khudiyev, Juliette Marion, Guanchun Rui, Jinuan Lin, Juliana Cherston, Atharva Sahasrabudhe, Joao Wilbert, Irmandy Wicaksono, Reed W. Hoyt, Anais Missakian, Lei Zhu, Chu Ma, John Joannopoulos, Yoel Fink*. Single fiber enables acoustic fabrics via nanometer scale vibrations. Nature 603 (2022) 616.

[2] Shengtai Qian, Mingyang Liu, Yuhai Dou, Yoel Fink and Wei Yan*. A ‘Moore’s law’ for fibers enables intelligent fabrics. National Science Review (2022)

Figure 1
(Invited) rubbery Electronics to Seamlessly Integrate with Human Body
Authors: Yu Cunjiang
Published: September 2023

Electronics that can seamlessly integrate with human body could have significant impact in medical diagnostic, therapeutics. However, seamless integration is a grand challenge because of the distinct nature between electronics and human body. Conventional electronics are rigid and planar, made out of rigid materials. Human body are soft, deformable and curvilinear, comprised of biological materials, organs and tissues. This talk will introduce our solution to address the challenge through the invention of a new class of electronics, namely rubbery electronics. Rubbery electronics is constructed all based on elastic rubber electronic materials of semiconductors, conductors and dielectrics, which possesses tissue-like softness and mechanical stretchability to allow seamless integration with soft deformable tissues and organs. Rubbery electronic materials (particularly semiconductors) and device innovations set the foundation for rubbery electronics. This presentation will feature the development and understanding of rubbery semiconductors, rubbery transistors, integrated electronics, sensors and bioelectronics. In addition, rubbery electronics enabled functional systems will also be demonstrated. As a platform technology, rubbery electronics opens up numerous opportunities for many different fields such as healthcare, robotics, human-machine interfaces, artificial intelligence.
Aptamer-Based Electric-Double -Layer (EDL) Extended-Gated FET Biosensor for Detection of Cadmium Ion
Authors: Kuo TzuHan Han , Wang Yu-Lin Lin , Lin Chia Kai , Paulose Akhil K
Published: September 2023

Cadmium ion (Cd2+) is a highly toxic heavy metal pollutant. It causes irreversible damage to human health even at low doses due to a long biological half-life and strong bioaccumulation. Common heavy metal detection includes Inductively Coupled Plasma with Atomic Emission, Spectroscopy (ICP-AES), Inductively coupled plasma mass spectrometry (ICP-MS), Flame Atomic Absorption Spectrophotometry (FAAS), and Graphite Furnace Atomic Absorption Spectrometry (GFAAS), and. However, these technologies are high-cost, time-consuming, complicated operations, and can't be detected immediately and accurately.

In this study, we developed an electric double-layer (EDL) extended-gate field effect transistor sensor based on aptamers to detect cadmium ions (Cd2+). Use N-channel enhanced-mode MOSFETs to connect the extended-gate array chips with aptamer modified. The aptamers were self-assembled on the gold electrode surface through Au-S bonds. Since the aptamer has a specific binding ability to cadmium ions, it will bind to the aptamer to form a stem-loop structure. The gate voltage changes caused by the structure change and then amplify the electrical signal through the transconductance of the field effect transistor. The linear detection range of this sensor for cadmium ions is from 1nM to 10uM. The Cd2+ calibration curve is shown a high correlation coefficient (R2 = 0.99001) and an excellent detection limit as low as 99.5 nＭ. Importantly, it responds to Cd2+ within 10 seconds. The sensor exhibits high selectivity in the presence of other heavy metals such as arsenic, chromium, lead, and mercury for electrical signal measurements. It also can be reused without significant signal attenuation.

The advantages of this method are convenient portability, short detection time, high sensitivity, and simple operation. It has a good prospect for detection in the daily life of cadmium environmental pollution.

Figure 1
Development of Molecularly Imprinted Polymer Nanoparticles with High Affinity and Its Application to Electrochemical Biosensors
Authors: Man Youyuan , Nishitani Shoichi , Sakata Toshiya
Published: September 2023

Molecularly imprinted polymers (MIPs) have the potentials to be low-cost and stable alternatives to natural receptors such as enzymes and antibodies for biosensors. In our group, we have been developing enzyme-/antibody-free electrochemical biosensors with the MIP-coated electrodes [1,2]. However, the conventional polymerization methods for MIPs have the limitations such as their heterogeneities that reduce high binding affinity sites and the presence of residual templated molecules, which are detrimental to biomolecular recognition. To address these issues, we have synthesized molecularly imprinted polymer nanoparticles (nano-MIPs) with virtually free of heterogeneous templates and higher affinity for target biomolecules by using a solid-phase approach synthesis method [3]. In this study, we have focused on the biomarkers such as human serum albumin (HSA) and glycated albumin (GA) for diabetes and then synthesized the redox-labeled HSA-templated nano-MIPs (HNMs) and GA-templated nano-MIPs (GNMs) for the electrochemical biosensor (Figure 1). The fundamental characteristics of HNMs and GNMs such as chemical composition, particle size, and binding affinity have been evaluated by using proton nuclear magnetic resonance (1H NMR), dynamic light scattering (DLS), atomic force microscopy (AFM), cyclic voltammetry (CV), isothermal titration calorimetry (ITC), and surface plasmon resonance (SPR).

References

Kajisa, T.; Sakata, T. ACS Appl. Mater. Interfaces 2018,10, 34983–34990.

Sakata, T.; Nishitani, S.; Kajisa, T. RSC Advances 2020, 10, 16999–17013.

Canfarotta, F. et al. Nat. Protoc. 2016, 3, 443-455.

Figure 1
(Invited) liquid Biopsy Tool: Integrated Aiot Digital Bead-Based Sensor for Molecular-Fingerprint Profiling of Extracellular Vesicles
Authors: Lin Hsing-Ying , Huang Chen-Han , Hsu Peng-Wei , Chen Yi-Chien , Liu Yu-He , Wei Zhi-Yang , Chen Chia-Hung , Ho Li-Hsien , Yao Hsien-Wen , Lin Ting-Yi , Chou I-Hsuan , Chung Yun-Hsien , Lan Wei-Chun , Yen Tao-Yun , Chueh Hua-En
Published: September 2023

Development of liquid biopsies for non-invasive tumor characterization techniques shows great promise for real-time monitoring of tumor recurrence, progression, and treatment response. To better assess the various tumor evolution, cellular heterogeneity, consequent drug-resistance mechanisms, it is critical to screen proteins and nucleic acids of extracellular vesicles (EVs) in biofluids. We are developing an integrated sensitive digital bead-based sensor enabling evaluation of molecular profiling of extracellular vesicles in glioblastoma. The tumor relevant genetic information in EVs is enriched by antibody-specific magnetic beads and amplified by reverse transcription recombinase polymerase amplification with CRISPR/Cas13a system in twenty-five thousand droplets, and results are analyzed by a miniaturized imaging device. The niches of our developing technique include a) the streamlined sample preparation process and miniaturized detection system enable the ultrasensitive detection of mRNA in extracellular vesicles within one and half hour, b) the fluorescent signal-to-noise ratio in each 40-µm sized droplet is significantly enhanced via using a simple Cas13a assay and triggering greater than 104 turnovers of fluorescent reporters on a chip, c) real-time image data are transferred to a cloud-based server to be classified with trained YOLOv5 models and RNAomic results are displayed on the Raspberry Pi touchscreen. This system allows use by lower skill health care workers. This approach can provide inexpensive, rapid, and treatment-informative diagnostics for underserved regions, and underfunded health care systems. It could be further developed for other cancers, leading up the speed of diagnosis and treatment decision-making in using liquid biopsy, thus find widespread use in global health.

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(Invited) micro-Nanoscale Living Lasers for Healthcare Applications
Authors: Chen Yu-Cheng , Nie Ningyuan
Published: September 2023

Have you imagined of carrying a laser in your cell or body? Lasers are ubiquitous in our daily lives from industry, communication to medicine. The scale of lasers has also shrunk down to micron and nanoscales. As the scale of laser become smaller, the functions of lasers have also been redefined by transforming living biologicals into micro- and nanoscale lasers, so called living lasers. Such tiny lasers could therefore be used to detect or monitor critical chemical or physical signals in living cells or human body with distinctive sensitivity and intensity. In this talk, I will introduce the recent development of biological lasers and showcase how this interdisciplinary technology bridges laser physics and biology to tackle biomedical problems. In the first part, the talk will be focused on its application in detecting cancer and neurological diseases. In the second part, I will introduce how tiny lasers can be transformed with intelligent functions for information encoding and healthcare. This will cover applications including sensing at multiscales in biology, imaging in tissues, tracking and monitoring, as well as biomedical devices. Finally, discussion and outlook will be made on the strategies to pioneer novel on-chip and wearable laser devices for future medical diagnosis and bio-intelligent technology.

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(Invited) From Lab to Fab: The Journey of Waveguide-Enhanced Raman Spectroscopy
Authors: Michon Jerom , Kita Derek , Hu Juejun
Published: September 2023

Waveguide-enhanced Raman spectroscopy (WERS) is an emerging technology that uses on-chip optical waveguides to perform real-time detection of biochemical molecules. Compared to traditional Raman systems based on bulk optics, WERS offers significant sensitivity enhancement capitalizing on the strong light-matter interactions in nanophotonic waveguides, and also enables a low-cost, compact, and scalable sensing platform ideally suited for in-line process monitoring in the biopharmaceutical industry. This talk will summarize the work in my group as well as our collaborators, highlighting the development of WERS from a laboratory curiosity to its imminent industry deployment.
A Tactile Sensing System Based on the Triboelectric Nanogenerator for Prosthetic Application
Authors: Shen Li Chien , Chang Kuie-Bin , Lin Zong-Hong , Hu Jin-Jia
Published: September 2023

The distribution of interfacial stress between the amputee's residual limb and the prosthetic socket is thought to be directly related to comfort. Prosthetic sockets are custom-made and the current technology is very mature, whether, by manual molding or 3D scanning, the prosthesis can be made to fit the patient's residual limb, but when the patient actually wears the prosthesis, the wearer may still experience discomfort due to long wear time and foreign body friction. Therefore, researchers have been interested in quantifying these interfacial stresses in order to assess the extent of any potential damage to the residual limb and to reduce the cost of prosthetic fabrication by avoiding repetitive changes to the prosthesis. However, the existing pressure sensors are not only expensive but also have compatibility problems with the residual limb and are prone to instability under the influence of the external environment, which greatly affects the actual force readings in the area. Here, we developed a tactile sensor by triboelectric nanogenerator(TENG), which collects force energy by triboelectric effect, and its wide material selection, easy fabrication, and self-driving properties are receiving more and more attention. In our research, we propose to develop a multi-point array tactile sensor based on two materials: polydimethylsiloxane (PDMS) and polycaprolactone (PCL). The surface of PDMS has a droplet microstructure, and PCL is made into a nanofiber film by electrospinning to increase the specific surface area of the material in contact to improve the output characteristics of the device and achieve a larger detection range and sensitivity. In addition to the excellent durability at 10,000 cycles, the characteristics of the device also show good stability at different humidity and temperature. Finally, we integrated this multi-point array sensor with a multi-channel measurement system, attached it to the contact interface of a 3D-printed residual limb and prosthetic model, and collected real-time correspondence signals from the compressed side to demonstrate the feasibility of this application. We believe that this novel design offers a new approach to improve the comfort of prosthetic wear for amputees and has considerable potential.
(Invited) wearable Elastography Via Surface Mechano-Acoustic Sensing for Continuous Monitoring of Tissue Stiffness
Authors: Wu Changsheng , Li Chenhang , Wang Heling , Huang Yonggang , Rogers John , Ni Xiaoyue
Published: September 2023

Recent progress in wearable devices provides new opportunities for precise, non-invasive, long-term recording of body mechanics. The soft device incorporating a single MEMS accelerometer captures subtle vibration of the skin with a resolution of 1×10-4 g/√Hz in the frequency range from 0 to 800 Hz. In this study, we introduce an on-body mechano-acoustic sensing technology based on a skin-mounted accelerometer array to assess the mechanical profiles of subdermal tissues in-vivo, similar to seismology. A system-level wearable device construction, optimized for a comfortable skin interface and high precision, incorporates a broadband dual-accelerometer sensor, an audio actuator, and a Bluetooth System-on-Chip and enables a wireless, automated operation. An automated algorithm, leveraging the spectral analysis of surface waves (SASW) methods, computes the depth-sensitive, elastic modulus information of the propagation media from the mechanical dispersion relationship. Comprehensive theoretical and experimental investigation on bi-layer phantom materials and biological tissues, with a storage moduli range of 19–1439 kPa, demonstrates the capability of rapid and robust evaluation of modulus in a depth range of 2–46 mm. The device identifies the softening of porcine tissues with increasing injected water content and the changes of modulus of muscle under different levels of tension. The results are in agreement with the in-parallel Ultrasound Elastography measurements. A quantitative assessment of the stiffness profile of the bicep brachii and rectus femoris muscle during gym exercises demonstrate the device operation in an ambulant environment for a non-invasive and continuous assessment of deep tissue stiffness with a temporal resolution of 0.5 s.
Wafer-Scale Nanocracks Enable Single-Molecule Detection and on-Site Analysis
Authors: LU LI-Chia , Chang Yu-Ling , Lai I-Chun , Chang Sih-Ｗei , Sun Aileen Y. , Chen Hsuen-Li , Wan Dehui
Published: September 2023

Large-area surface-enhanced Raman spectroscopy (SERS) sensing platforms displaying ultrahigh sensitivity and signal uniformity have potentially enormous sensing applicability, but they are still challenging to prepare in a scalable manner. In this study, silver nanopaste (AgNPA) was employed to prepare a wafer-scale, ultrasensitive SERS substrate. The self-generated, high-density Ag nanocracks (NCKs) with small gaps could be created on Si wafers via a spin-coating process, and provided extremely abundant hotspots for SERS analyses with ultrahigh sensitivity—down to the level of single molecules (enhancement factor: ca. 1010; detection limit: ca. 10–18 M)—and great signal reproducibility (variation: ca. 3.6%). Moreover, the Ag NCK arrays demonstrated broad applicability and practicability for on-site detection when combined with a portable 785 Raman spectrometer. This method allowed the highly sensitive detection of a diverse range of analytes (benzo[a]pyrene, di-2-ethylhexyl phthalate, aflatoxins B1, zearalenone, ractopamine, salbutamol, sildenafil, thiram, dimethoate, and methamidophos). In particular, pesticides are used extensively in agricultural production. Unfortunately, they can affect the environment and human health as a result of acute toxicity. Therefore, the simultaneous label-free detection of three different pesticides was demonstrated. Finally, the SERS substrates are fabricated through a simple, efficient, and scalable process that offers new opportunities for mass production.

Figure 1
Development of Wearable Microneedle-Based Platform for Real-Time Biomarkers Sensing
Authors: Fan Kai , Liu Kuei-Lin , Chung Jun-Hsuan , Lin Zong-Hong
Published: September 2023

The wearable device technology plays a huge role in the healthcare sector owing to the aging global population and increased acquisition of the internet of things (IoT). Further, the Coronavirus Disease-2019 (COVID-19) pandemic has accelerated the emergence of wearable medical devices in the market. The patients with chronic diseases are more focused on tracking single or multiple nutrients and biomarkers in the body. Diabetes is a classic example of chronic disease where the patients need to monitor their blood glucose level for a long time. In addition, diabetic patients also face electrolyte imbalance which gives rise to several other diseases. There is an immense urgency to develop a sensing platform that can detect the essential ions as well as biomarkers from the interstitial fluid (ISF) as it contains valuable information about the physiological status of a person. According to Centers for Disease Control and Prevention (CDC), imbalance of sodium concentration in the body may lead to stroke, hypertension, and epilepsy; for potassium: arrhythmia, chronic kidney disease (CKD), and dizziness; for calcium: depression, osteoporosis, and other bone-related disease; for pH of body fluid: urinary tract infection, respiratory acidosis, and sleep apnea. Within this advent of wearables, microneedle (MN)-based transdermal sensors are well positioned to play a key role in combining the significant benefits of dermal interstitial fluid (ISF) as a source of clinical indicators and minimally invasive skin puncturing to allow the collection of real-time diagnostic data. In this context, we have developed a MNs based versatile platform for the transdermal amperometric detection of glucose and different clinically relevant biomarkers such as K+, Na+, Ca2+ in the body fluid in a robust, reliable, and cost-effective way. Here, stainless steel microneedle (SS-MN) is used as an ideal candidate for multiplex sensing due to its great chemical stability as well as the rigidity for accurate and painless puncture. The device is fabricated with ion selective electrode (ISM) coating on each needle for their corresponding electrolyte and enzyme for glucose detection. In vitro experiments performed in artificial ISF samples yielded excellent sensitivity and a good linear response. The sensor is successfully applied for in vivo detection of glucose and these ions in SD rats for validating their feasibility as a real-time sensing device. Overall, this developed concept comprises of significant progress in the sensing of glucose and other ions in relation to an electrolyte imbalance in the humans that holds relevance in controlling several diseases.