Suppression of surface optical phonon scattering by AlN interfacial layers for mobility enhancement in MoS FETs.

Molybdenum disulfide (MoS) has been attracting attention for its theoretically outstanding electrical characteristics such as an appropriate bandgap, high mobility, and atomically thin nature. However, when MoS is used to fabricate field-effect transistors (FETs), it is difficult to achieve intrinsically good performance due to severe scattering caused by charged impurities (CIs), surface roughness, and surface optical phonons (SOPs). Since SOP scattering is widely acknowledged as the dominant mechanism degrading mobility at room temperature, in this study, we aim to suppress the SOP scattering originating from high-κ oxide dielectrics (such as AlO with a low SOP energy of 48.

Woven Fabric Muscle for Soft Wearable Robotic Application Using Two-Dimensional Zigzag Shape Memory Alloy Actuator.

In this study, we propose a fabric muscle based on the Zigzag Shape Memory Alloy (ZSMA) actuator. Soft wearable robots have been gaining attention due to their flexibility and the ability to provide significant power support to the user without hindering their movement and mobility. There has been an increasing focus on the research and development of fabric muscles, which are crucial components of these robots.

Imidazole-based artificial synapses for neuromorphic computing: a cluster-type conductive filament controllable nanocluster nucleation.

Memristive synapses based on conductive bridging RAMs (CBRAMs) utilize a switching layer having low binding energy with active metals for excellent analog conductance modulation, but the resulting unstable conductive filaments cause fluctuation and drift of the conductance. This tunability-stability dilemma makes it difficult to implement practical neuromorphic computing. A novel method is proposed to enhance the stability and controllability of conductive filaments by introducing imidazole groups that boost the nucleation of Cu nanoclusters in the ultrathin polymer switching layer through the initiated chemical vapor deposition (iCVD) process.

Preventing Vanishing Gradient Problem of Hardware Neuromorphic System by Implementing Imidazole-Based Memristive ReLU Activation Neuron.

With advances in artificial intelligent services, brain-inspired neuromorphic systems with synaptic devices are recently attracting significant interest to circumvent the von Neumann bottleneck. However, the increasing trend of deep neural network parameters causes huge power consumption and large area overhead of a nonlinear neuron electronic circuit, and it incurs a vanishing gradient problem. Here, a memristor-based compact and energy-efficient neuron device is presented to implement a rectifying linear unit (ReLU) activation function.

Design and Control of Lightweight Bionic Arm Driven by Soft Twisted and Coiled Artificial Muscles.

Twisted and coiled actuators (TCAs), which are light but capable of producing significant power, were developed in recent times. After their introduction, there have been numerous improvements in performance, including development of techniques such as actuation strain and heating methods. However, the development of robots using TCA is still in its early stages.

Spatially isolated neutral excitons clusters on trilayer MoS.

In spite of having a large exciton binding energy, two-dimensional (2D) transition metal dichalcogenides (TMDs) are limited as light-emitting materials because the spectral weight of neutral excitons decreases exponentially with increasing the excitation density. That is, neutral excitons easily transfer to trions, and exciton-exciton annihilation (EEA) occurs due to the strengthening of exciton kinetic energy in the layered structure. In here, we come up with an isolated neutral exciton system, maintaining its high spectral weight when the carrier density increased, which is achieved MoS clusters on a MoS trilayer directly synthesized by metal-organic chemical vapor deposition (MOCVD).

Wafer-Scale Uniform Growth of an Atomically Thin MoS Film with Controlled Layer Numbers by Metal-Organic Chemical Vapor Deposition.

The growth control of a molybdenum disulfide (MoS) thin film, including the number of layers, growth rate, and electrical property modulation, remains a challenge. In this study, we synthesized MoS thin films using the metal-organic chemical vapor deposition (MOCVD) method with a 2 inch wafer scale and achieved high thickness uniformity according to the positions on the substrate. In addition, we successfully controlled the number of MoS layers to range from one to five, with a growth rate of 10 min per layer.

Shape Estimation of Soft Manipulator Using Stretchable Sensor.

The soft robot manipulator is attracting attention in the surgical fields with its intrinsic softness, lightness in its weight, and safety toward the human organ. However, it cannot be used widely because of its difficulty of control. To control a soft robot manipulator accurately, shape sensing is essential.

Conductive-bridging random-access memories for emerging neuromorphic computing.

With the increasing utilisation of artificial intelligence, there is a renewed demand for the development of novel neuromorphic computing owing to the drawbacks of the existing computing paradigm based on the von Neumann architecture. Extensive studies have been performed on memristors as their electrical nature is similar to those of biological synapses and neurons. However, most hardware-based artificial neural networks (ANNs) have been developed with oxide-based memristors owing to their high compatibility with mature complementary metal-oxide-semiconductor (CMOS) processes.

Low-Thermal-Budget Doping of 2D Materials in Ambient Air Exemplified by Synthesis of Boron-Doped Reduced Graphene Oxide.

Graphene oxide (GO) doping and reduction allow for physicochemical property modification to suit practical application needs. Herein, the challenge of simultaneous low-thermal-budget heteroatom doping of GO and its reduction in ambient air is addressed through the synthesis of B-doped reduced GO (B@rGO) by flash irradiation of boric acid loaded onto a GO support with intense pulsed light (IPL). The effects of light power and number of shots on the in-depth sequential doping and reduction mechanisms are investigated by ex situ X-ray photoelectron spectroscopy and direct millisecond-scale temperature measurements (temperature >1600 °C, < 10-millisecond duration, ramping rate of 5.

Polymer Analog Memristive Synapse with Atomic-Scale Conductive Filament for Flexible Neuromorphic Computing System.

With the advent of artificial intelligence (AI), memristors have received significant interest as a synaptic building block for neuromorphic systems, where each synaptic memristor should operate in an analog fashion, exhibiting multilevel accessible conductance states. Here, we demonstrate that the transition of the operation mode in poly(1,3,5-trivinyl-1,3,5-trimethyl cyclotrisiloxane) (pV3D3)-based flexible memristor from conventional binary to synaptic analog switching can be achieved simply by reducing the size of the formed filament. With the quantized conductance states observed in the flexible pV3D3 memristor, analog potentiation and depression characteristics of the memristive synapse are obtained through the growth of atomically thin Cu filament and lateral dissolution of the filament via dominant electric field effect, respectively.

Early Intranasal Vasopressin Administration Impairs Partner Preference in Adult Male Prairie Voles ().

Research supports a modulatory role for arginine vasopressin (AVP) in the expression of socially motivated behaviors in mammals. The acute effects of AVP administration are demonstrably pro-social across species, providing the justification for an ever-increasing measure of clinical interest over the last decade. Combining these results with non-invasive intranasal delivery results in an attractive system for offering intranasal AVP (IN-AVP) as a therapeutic for the social impairments of children with autism spectrum disorder.

Efficacy and Safety of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil Fumarate in Asian Subjects with Human Immunodeficiency Virus 1 Infection: A Sub-Analysis of Phase 3 Clinical Trials.

The efficacy and safety of a single tablet regimen (STR) of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF) were analyzed in Phase 3 clinical trials in antiretroviral therapy (ART)-naïve and ART-experienced Asian subjects infected with human immunodeficiency virus (HIV)-1. Studies GS-US-236-102 and GS-US-236-103 were randomized, double-blind, placebo-controlled, 144-week studies conducted in ART-naïve subjects, comparing E/C/F/TDF versus efavirenz (EFV)/F/TDF or ritonavir-boosted atazanavir (ATV+RTV) plus emtricitabine/tenofovir DF (F/TDF), respectively. Studies GS-US-236-115 and GS-US-236-121 were randomized, open-label, 96-week long conducted in ART-experienced subjects, who switched to E/C/F/TDF from ritonavir-boosted protease inhibitors (PI+RTV)+F/TDF, or non-nucleoside reverse transcriptase inhibitors (NNRTI)+F/TDF regimens.

Flexible Nonvolatile Polymer Memory Array on Plastic Substrate via Initiated Chemical Vapor Deposition.

Resistive random access memory based on polymer thin films has been developed as a promising flexible nonvolatile memory for flexible electronic systems. Memory plays an important role in all modern electronic systems for data storage, processing, and communication; thus, the development of flexible memory is essential for the realization of flexible electronics. However, the existing solution-processed, polymer-based RRAMs have exhibited serious drawbacks in terms of the uniformity, electrical stability, and long-term stability of the polymer thin films.

Metal-etching-free direct delamination and transfer of single-layer graphene with a high degree of freedom.

A method of graphene transfer without metal etching is developed to minimize the contamination of graphene in the transfer process and to endow the transfer process with a greater degree of freedom. The method involves direct delamination of single-layer graphene from a growth substrate, resulting in transferred graphene with nearly zero Dirac voltage due to the absence of residues that would originate from metal etching. Several demonstrations are also presented to show the high degree of freedom and the resulting versatility of this transfer method.

Stretchable, multiplexed pH sensors with demonstrations on rabbit and human hearts undergoing ischemia.

Stable pH is an established biomarker of health, relevant to all tissues of the body, including the heart. Clinical monitoring of pH in a practical manner, with high spatiotemporal resolution, is particularly difficult in organs such as the heart due to its soft mechanics, curvilinear geometry, heterogeneous surfaces, and continuous, complex rhythmic motion. The results presented here illustrate that advanced strategies in materials assembly and electrochemical growth can yield interconnected arrays of miniaturized IrOx pH sensors encapsulated in thin, low-modulus elastomers to yield conformal monitoring systems capable of noninvasive measurements on the surface of the beating heart.

Elastomer surfaces with directionally dependent adhesion strength and their use in transfer printing with continuous roll-to-roll applications.

In this paper we present mechanics and materials aspects of elastomeric stamps that have angled features of relief on their surfaces, designed to enable control of adhesion strength by peeling direction, in a way that can be exploited in schemes for deterministic assembly by transfer printing. Detailed mechanics models capture the essential physics of interface adhesion in this system. Experiments with cylindrical stamps that have this design demonstrate their potential for use in a continuous, roller mode of operation.

Electrochemical transistors with ionic liquids for enzymatic sensing.

We report an enzymatic sensor based on an organic electrochemical transistor that uses a room temperature ionic liquid as an integral part of its structure and as an immobilization medium for the enzyme and the mediator.

Paper actuators made with cellulose and hybrid materials.

Recently, cellulose has been re-discovered as a smart material that can be used as sensor and actuator materials, which is termed electro-active paper (EAPap). This paper reports recent advances in paper actuators made with cellulose and hybrid materials such as multi-walled carbon nanotubes, conducting polymers and ionic liquids. Two distinct actuator principles in EAPap actuators are demonstrated: piezoelectric effect and ion migration effect in cellulose.

Integration of a surface-directed microfluidic system with an organic electrochemical transistor array for multi-analyte biosensors.

We report the integration of organic electrochemical transistors with a surface-directed microfluidic system. The end product is a chip in which an analyte solution is distributed in four separate measurement reservoirs, each containing a transistor that uses the analyte as an integral part of its device structure. The use of a surface-directed microfluidic system enables the distribution of the analyte solution without the application of external pressure.

Enhanced electrical percolation due to interconnection of three-dimensional pentacene islands in thin films on low surface energy polyimide gate dielectrics.

The role of lateral interconnections between three-dimensional pentacene islands on low surface energy polyimide gate dielectrics was investigated by the measurement of the surface coverage dependence of the charge mobility and the use of conducting-probe atomic force microscopy (CP-AFM). From the correlation between the electrical characteristics and the morphological evolution of the three-dimensionally grown pentacene films-based field-effect transistors, we found that during film growth, the formation of interconnections between the three-dimensional pentacene islands that are isolated at the early stage contributes significantly to the enhancement process of charge mobility. The CP-AFM current mapping images of the pentacene films also indicate that the lateral interconnections play an important role in the formation of good electrical percolation pathways between the three-dimensional pentacene islands.