Processes to enable hysteresis-free operation of ultrathin ALD Te p-channel field-effect transistors.

Recently, tellurium (Te) has been proposed as a promising p-type material; however, even the state-of-the-art results couldn't overcome the critical roadblocks for its practical applications, such as large - hysteresis and high off-state leakage current. We developed a novel Te atomic layer deposition (ALD) process combined with a TeO seed layer and AlO passivation to detour the limitations of p-type Te semiconducting materials. Also, we have identified the origins of high hysteresis and off current using the 77 K operation study and passivation process optimization.

Gamma-Irradiation-Induced Electrical Characteristic Variations in MoS Field-Effect Transistors with Buried Local Back-Gate Structure.

The impact of radiation on MoS-based devices is an important factor in the utilization of two-dimensional semiconductor-based technology in radiation-sensitive environments. In this study, the effects of gamma irradiation on the electrical variations in MoS field-effect transistors with buried local back-gate structures were investigated, and their related effects on AlO gate dielectrics and MoS/AlO interfaces were also analyzed. The transfer and output characteristics were analyzed before and after irradiation.

Demonstration of a low power and high-speed graphene/silicon heterojunction near-infrared photodetector.

The structure and process of the graphene/Si heterojunction near-infrared photodetector were optimized to enhance the operating speed limit. The introduction of a well-designed structure improved the rise time from 12.6 μs to 115 ns, albeit at the expense of the responsivity, which decreased from 1.

Demonstration of p-type stack-channel ternary logic device using scalable DNTT patterning process.

A p-type ternary logic device with a stack-channel structure is demonstrated using an organic p-type semiconductor, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). A photolithography-based patterning process is developed to fabricate scaled electronic devices with complex organic semiconductor channel structures. Two layers of thin DNTT with a separation layer are fabricated via the low-temperature deposition process, and for the first time, p-type ternary logic switching characteristics exhibiting zero differential conductance in the intermediate current state are demonstrated.

Dual-channel P-type ternary DNTT-graphene barristor.

P-type ternary switch devices are crucial elements for the practical implementation of complementary ternary circuits. This report demonstrates a p-type ternary device showing three distinct electrical output states with controllable threshold voltage values using a dual-channel dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]-thiophene-graphene barristor structure. To obtain transfer characteristics with distinctively separated ternary states, novel structures called contact-resistive and contact-doping layers were developed.

Demonstration of Anti-ambipolar Switch and Its Applications for Extremely Low Power Ternary Logic Circuits.

Anti-ambipolar switch (AAS) devices at a narrow bias region are necessary to solve the intrinsic leakage current problem of ternary logic circuits. In this study, an AAS device with a very high peak-to-valley ratio (∼10) and adjustable operating range characteristics was successfully demonstrated using a ZnO and dinaphtho[2,3-:2',3'-]thieno[3,2-]thiophene heterojunction structure. The entire device integration was completed at a low thermal budget of less than 200 °C, which makes this AAS device compatible with monolithic 3D integration.

Performance Degradation in Graphene-ZnO Barristors Due to Graphene Edge Contact.

The physical and chemical characteristics of the edge states of graphene have been studied extensively as they affect the electrical properties of graphene significantly. Likewise, the edge states of graphene in contact with semiconductors or transition-metal dichalcogenides (TMDs) are expected to have a strong influence on the electrical properties of the resulting Schottky junction devices. We found that the edge states of graphene form chemical bonds with the ZnO layer, which limits the modulation of the Fermi level at the graphene-semiconductor junction, in a manner similar to Fermi level pinning in silicon devices.

Dynamic band alignment modulation of ultrathin WO/ZnO stack for high on/off ratio field-effect switching applications.

A two-dimensional (2D) WO/ZnO stack reveals a unique carrier transport behavior, which can be utilized as a novel device element to achieve a very high on/off ratio (>10) and an off current density lower than 1 nA cm. These unique behaviors are explained by a dynamic band alignment between WO and ZnO, which can be actively modulated by a gate bias. The performance of FET utilizing the WO/ZnO stack is comparable to those of other 2D heterojunction devices; however, it has a unique benefit in terms of process integration because of very low temperature process capability (T < 110 °C).

Effects of Bath Composition and P Contents on the Defects of NiP Layer in Electroless Nickel Immersion Gold Process.

Electroless nickel immersion gold (ENIG) has been widely used for surface finishing in PCB industry, however surface defects are sometimes found during PCB soldering process. These defects cause failures in soldering on PCB and consequently cause poor safety probability of products. The formation mechanism of the defects in the NiP layer was investigated.

Toward all-day wearable health monitoring: An ultralow-power, reflective organic pulse oximetry sensing patch.

Pulse oximetry sensors have been playing a key role as devices to monitor elemental yet critical human health states. Conventional pulse oximetry sensors, however, have relatively large power consumption, impeding their use as stand-alone, continuous monitoring systems that can easily be integrated with everyday life. Here, we exploit the design freedom offered by organic technologies to realize a reflective patch-type pulse oximetry sensor with ultralow power consumption.

A 274µW clock synchronized wireless body area network IC with super-regenerative RSSI for biomedical ad-hoc network system.

A clock synchronized multi-node wireless body area network (WBAN) transceiver IC with super-regenerative RSSI is proposed for biomedical ad-hoc network system. The ad-hoc network makes stable communication even in the harsh human body channel condition (<;-50 dB attenuation) with low-power consumption. The proposed system consists of two types of IC - a hub and node IC.

Sticker-type ECG/PPG concurrent monitoring system hybrid integration of CMOS SoC and organic sensor device.

The sticker-type sensor system is proposed targeting ECG/PPG concurrent monitoring for cardiovascular diseases. The stickers are composed of two types: Hub and Sensor-node (SN) sticker. Low-power CMOS SoC for measuring ECG and PPG signal is hybrid integrated with organic light emitting diodes (OLEDs) and organic photo detector (OPD).

A graphene barristor using nitrogen profile controlled ZnO Schottky contacts.

We have successfully demonstrated a graphene-ZnO:N Schottky barristor. The barrier height between graphene and ZnO:N could be modulated by a buried gate electrode in the range of 0.5-0.

A 540-[Formula: see text] Duty Controlled RSSI With Current Reusing Technique for Human Body Communication.

An ultra-low-power duty controlled received signal strength indicator (RSSI) is implemented for human body communication (HBC) in 180 nm CMOS technology under 1.5 V supply. The proposed RSSI adopted 3 following key features for low-power consumption; 1) current reusing technique (CR-RSSI) with replica bias circuit and calibration unit, 2) duty controller, and 3) reconfigurable gm-boosting LNA.

A Wearable EEG-HEG-HRV Multimodal System With Simultaneous Monitoring of tES for Mental Health Management.

A multimodal mental management system in the shape of the wearable headband and earplugs is proposed to monitor electroencephalography (EEG), hemoencephalography (HEG) and heart rate variability (HRV) for accurate mental health monitoring. It enables simultaneous transcranial electrical stimulation (tES) together with real-time monitoring. The total weight of the proposed system is less than 200 g.

A multimodal stress monitoring system with canonical correlation analysis.

The multimodal stress monitoring headband is proposed for mobile stress management system. It is composed of headband and earplugs. Electroencephalography (EEG), hemoencephalography (HEG) and heart-rate variability (HRV) can be achieved simultaneously in the proposed system for user status estimation.

Distinct pathophysiologic mechanisms of septic acute kidney injury: role of immune suppression and renal tubular cell apoptosis in murine model of septic acute kidney injury.

Objective: Sepsis is the most common cause of acute kidney injury in critically ill patients; however, the mechanisms leading to acute kidney injury in sepsis remain elusive. Although sepsis has been considered an excessive systemic inflammatory response, clinical trials that inhibit inflammation have been shown to have no effect. The purpose of this study was to examine the pathophysiology of septic acute kidney injury focusing on immune responses and renal tubular cell apoptosis by providing an on-site quantitative comparison between septic- and ischemia/reperfusion-induced acute kidney injury.

Interaction of glycopolymers with human hematopoietic cells from cord blood and peripheral blood.

Polystyrene derivatives, poly[N-pvinylbenzyl-O-D-glucopyranosyl-(1-4)-D-glucoamide] (PV Maltose) and poly[N-p-vinylbenzyl-O-mannopyranosyl-(1-4)-D-glucoamide] (PV Mannose), which contain glucose and mannose moieties, respectively, have the specific binding ability with murine hematopoietic cells. In this study, we confirm the ability of these glycopolymers to interact specifically with human hematopoietic stem cells (HSCs) and mature cells derived from human cord blood (CB) and peripheral blood (PB). Using fluorescence isothiocyanate (FITC)-labeled glycopolymers, we observed that 98% to 93% of hematopoietic cells interacted very strongly with PV Mannose, and 63% of CB and 29% PB interacted with PV Maltose.

Anxiolytic-like effects of obovatol isolated from Magnolia obovata: involvement of GABA/benzodiazepine receptors complex.

This experiment was performed to investigate whether obovatol isolated from the leaves of Magnolia obovata has anxiolytic-like effects through GABA-benzodiazepine-receptors Cl(-) channel activation. The anxiolytic-like effects of obovatol in mice were examined using the elevated plus-maze and the automatic hole-board apparatus. Oral administration of obovatol (0.