Low Voltage Operation Research Articles

High-Performance Low-Voltage Transparent Metal-Semiconductor-Metal Ultraviolet Photodetectors Based on Ultrathin Gold Asymmetric Interdigitated Electrodes.

A high-performance, low-voltage, transparent, metal-semiconductor-metal ultraviolet (UV) photodetector (PD) is proposed and experimentally demonstrated, based on gold (Au) asymmetric interdigitated (aIDT) electrodes with thicknesses well below 10 nm. A 7-nm-thick Au film, with a visible transmittance of 80.4% and a sheet resistance of 11.55 Ω/sq, is patterned into aIDT electrodes on a ZnO active layer, whose average visible transmittance is up to 74.3%. Meshing the pads further improves the overall transmittance of the device. Among all fabricated devices, the PD with the aIDT finger width ratio of 1:4 performs the best. Very low dark currents are achieved at 0, 0.5 and 1 V, allowing for high responsivities and specific detectivities to the UV light. It is also a fast device, especially under the biases of 0.5 and 1 V. The comprehensive performances are comparable and even superior to those of the reported devices. The asymmetric Schottky junctions induced by the aIDT electrodes under UV illumination are the main mechanism for the low-voltage operation of our transparent PD, which is promising to be applied widely.

Hydrogen Bonding-Assisted Complete Ferroelectric β-Phase Conversion in Poly(vinylidene fluoride) Thin Films: Exhibiting an Excellent Memory Window and Long Retention.

Organic nonvolatile memory with low power consumption is a critical research demand for next-generation memory applications. Ferroelectric switching characteristics of poly(vinylidene fluoride) (PVDF) thin films modified with a trace amount of hydrated Cu salt (CuCl2·2H2O) are explored in the present study. Herein, a Cu salt-mediated PVDF (Cu/PVDF) thin film with preferential edge-on β-crystallites is fabricated through the orientation-controlled spin coating (OCSC) technique. This work proposes a convenient and effective approach to produce edge-on-oriented electroactive PVDF thin films with a high degree of polar β-phase, so as to realize the favorable switching under low operating voltages. Herein, chemically modified PVDF is anticipated to form a complex intermediate, which attains its stability by undergoing favorable hydrogen bonding that reorients the C-C structure of PVDF to obtain the β-conformation. Such information is verified by X-ray photoelectron spectroscopy (XPS). Grazing incidence Fourier transform infrared (GI-FTIR) spectroscopy revealed that the Cu salt incorporated into the PVDF matrix favored the formation of the electroactive β-phase with edge-on crystallite lamellae. Consequently, the Cu/PVDF thin film demonstrates a good contrast between electric field-assisted written and erased data bits in the piezoresponse force microscopy (PFM) phase image. Furthermore, to obtain the ferroelectric memory window, a metal-ferroelectric-insulator-semiconductor (MFIS) diode with Cu/PVDF as a ferroelectric layer has been fabricated. The capacitance-voltage (C-V) characteristic of the MFIS diode exhibits a memory window of 12 V with a long-term retention behavior (∼longer than 7 days). In a nutshell, we tried to represent a clear understanding of the interfacial interactions of the Cu salt with PVDF, which favor the edge-on formation that results in the promising low-voltage ferroelectric switching and excellent retention response, where any additional electrical poling and/or external stretching is completely possible to be ruled out, thus offering a new prospect for the evolution of devices with long-lasting nonvolatile memories.

Integrated internal ion-gated organic electrochemical transistors for stand-alone conformable bioelectronics.

Organic electronics can be biocompatible and conformable, enhancing the ability to interface with tissue. However, the limitations of speed and integration have, thus far, necessitated reliance on silicon-based technologies for advanced processing, data transmission and device powering. Here we create a stand-alone, conformable, fully organic bioelectronic device capable of realizing these functions. This device, vertical internal ion-gated organic electrochemical transistor (vIGT), is based on a transistor architecture that incorporates a vertical channel and a miniaturized hydration access conduit to enable megahertz-signal-range operation within densely packed integrated arrays in the absence of crosstalk. These transistors demonstrated long-term stability in physiologic media, and were used to generate high-performance integrated circuits. We leveraged the high-speed and low-voltage operation of vertical internal ion-gated organic electrochemical transistors to develop alternating-current-powered conformable circuitry to acquire and wirelessly communicate signals. The resultant stand-alone device was implanted in freely moving rodents to acquire, process and transmit neurophysiologic brain signals. Such fully organic devices have the potential to expand the utility and accessibility of bioelectronics to a wide range of clinical and societal applications.

Inkjet‐Printed Tungsten Oxide Memristor Displaying Non‐Volatile Memory and Neuromorphic Properties

AbstractPrinted electronics including large‐area sensing, wearables, and bioelectronic systems are often limited to simple circuits and hence it remains a major challenge to efficiently store data and perform computational tasks. Memristors can be considered as ideal candidates for both purposes. Herein, an inkjet‐printed memristor is demonstrated, which can serve as a digital information storage device, or as an artificial synapse for neuromorphic circuits. This is achieved by suitable manipulation of the ion species in the active layer of the device. For digital‐type memristor operation resistive switching is dominated by cation movement after an initial electroforming step. It allows the device to be utilized as non‐volatile digital memristor, which offers high endurance over 12 672 switching cycles and high uniformity at low operating voltages. To use the device as an electroforming‐free, interface‐based, analog‐type memristor, anion migration is exploited which leads to volatile resistive switching. An important figure of merits such as short‐term plasticity with close to biological synapse timescales is demonstrated, for facilitation (10–177 ms), augmentation (10s), and potentiation (35 s). Furthermore, the device is thoroughly studied regarding its metaplasticity for memory formation. Last but not least, the inkjet‐printed artificial synapse shows non‐linear signal integration and low‐frequency filtering capabilities, which renders it a good candidate for neuromorphic computing architectures, such as reservoir computing.

Impermeable Graphene Skin Increases the Heating Efficiency and Stability of an MXene Heating Element.

A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp2 planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.

Organic Electrochemical Transistors (OECTs): Advancements and Exciting Prospects for Future Biosensing Applications

Over the past few decades, the field of organic electronics has depicted proliferated growth, due to the advantageous characteristics of organic semiconductors, such as tunability through synthetic chemistry, simplicity in processing, cost-effectiveness, and low-voltage operation, to cite a few. Organic electrochemical transistors (OECTs) have recently emerged as a highly promising technology in the area of biosensing and flexible electronics. OECT-based biosensors are capable of sensing brain activities, tissues, monitoring cells, hormones, DNAs, and glucose. Sensitivity, selectivity, and detection limit are the key parameters adopted for measuring the performance of OECT-based biosensors. This article highlights the advancements and exciting prospects of OECTs for future biosensing applications, such as cell-based biosensing, chemical sensing, DNA/ribonucleic acid (RNA) sensing, glucose sensing, immune sensing, ion sensing, and pH sensing. OECT-based biosensors outperform other conventional biosensors because of their excellent biocompatibility, high transconductance, and mixed electronic–ionic conductivity. At present, OECTs are fabricated and characterized in millimeter and micrometer dimensions, and miniaturizing their dimensions to nanoscale is the key challenge for utilizing them in the field of nanobioelectronics, nanomedicine, and nanobiosensing.

Design of High Precision Temperature Sensor with Current Gain Compensation Technology for On-Chip Application

The integration of on-chip temperature sensors within various systems, industrial Internet of Things (IoT), and wireless sensor networks is greatly facilitated by their small size, cost-effectiveness, and capability to provide direct digital output. However, the diverse application scenarios pose challenges in designing these sensors. On one hand, real-time clock calibration demands high-precision temperature sensors, while on-chip heat management emphasizes compactness and low-voltage operation. Additionally, streamlining the calibration cost for mass production holds significant practical value. Addressing these challenges, this study systematically investigates on-chip complementary metal-oxide-semiconductor (CMOS) temperature sensors based on distinct signal domains processed by temperature readout circuits. Specifically, the research commences by analyzing the issues of several degeneracy points in the front-end circuit of a bipolar junction transistor (BJT) temperature sensor with current gain compensation technology. To address the intricate design challenges in advanced technologies and calibration complexities in industrial applications, dynamic component matching, current gain compensation, and chopper stabilization are harnessed. A novel dynamic current gain canceling technique for temperature readout is introduced, enhancing temperature measurement accuracy without incurring additional power consumption or area overhead. Ultimately, an all-digital CMOS temperature sensor is realized using the SMIC 55 nm CMOS process. Occupying a mere 0.29 mm2 of core area, the design operates efficiently across a wide supply voltage range of 1.2 V to 3.6 V. Covering a temperature spectrum from −40 °C to 125 °C, the sensor demonstrates a calibration error of just ±0.7 °C. This achievement is attributed to the incorporation of the proposed dynamic current gain compensation technique.

Dot-product computation and logistic regression with 2D hexagonal-boron nitride (h-BN) memristor arrays

This work reports on the hardware implementation of analog dot-product operation on arrays of two-dimensional (2D) hexagonal boron nitride (h-BN) memristors. This extends beyond previous work that studied isolated device characteristics towards the application of analog neural network accelerators based on 2D memristor arrays. The wafer-level fabrication of the memristor arrays is enabled by large-area transfer of CVD-grown few-layer (8 layers) h-BN films. Individual devices achieve an on/off ratio of >10, low voltage operation (∼0.5 V set/V reset), good endurance (>6000 programming steps), and good retention (>104 s). The dot-product operation shows excellent linearity and repeatability, with low read energy consumption (∼200 aJ to 20 fJ per operation), with minimal error and deviation over various measurement cycles. Moreover, we present the implementation of a stochastic logistic regression algorithm in 2D h-BN memristor hardware for the classification of noisy images. The promising resistive switching characteristics, performance of dot-product computation, and successful demonstration of logistic regression in h-BN memristors signify an important step towards the integration of 2D materials for next-generation neuromorphic computing systems.

Study of low-energy gamma-ray detection performance of silicon photomultiplier with LaBr3(Ce) scintillator

Recent progress in the field of scintillators and silicon photomultipliers (SiPM) has allowed development of new scintillation detectors capable of detecting low-energy X- and gamma-ray sources that are widely used in medicine, security and industry. Such scintillation detectors are compact, insensitive to magnetic fields, have low operation voltages and are functional at room temperature. These advantages of SiPM are considered to solve the main problems facing scintillation detectors in medicine and industry today. Development of detectors of low-energy electromagnetic radiation is relevant now. Scintillation detectors based on lutetium fine silicate, LaBr3(Ce), NaI and silicon avalanche photomultipliers offer a great potential for use for X- and gamma-ray detection. The present work demonstrates the gamma-ray detection performance of a new micropixel avalanche photodiode (MAPD) array (16 (4×4) elements – 15×15 cm) with a LaBr3(Ce) scintillator (15×15×30 mm) using 177Lu and 133Ba isotopes as the gamma-ray sources.

Smoothing electric power production with DFIG-based wind energy conversion technology by employing hybrid controller model

The operations of WPTSs needs to be regulated under both its linear and nonlinear operating behaviors in order to ensure the maximum possible wind power production with lowering costs. This involves developing robust control structures that can stringently handle WPTSs’ sophisticated operation. In efforts to achieve this objective, the previous studies proposed various control strategies that were widely employed for the adjustments of WPTSs’ mechanical components. Herein, this paper pursues a rarely studied electrical-component control approach by implementing IFOC-based MPPT strategy on a RSC of DFIG-based WPTS. The ultimate goal of this study is to maintain the electric power quality by regulating the signal THDs of the system’s rotor alternating current along with mitigating the switching transients. To this end, the performances of conventional PI, and FL-tuned PI (FLPI) controllers, under the system’s both normal voltage rating & low voltage operation—it was assumed to be 10% of normal voltage rating, are set to be evaluated. Furthermore, the overall simulation of a 2 MW power scaled-DFIG system comprising aerodynamic model, electrical system model, control system model, and the controller models was implemented in MATLAB-SIMULINK environment in testing the effectiveness of the proposed approach based on a rated wind speed of 10 m/s. Accordingly, the THD factors of rotor alternating current are resulted to be 9.15% with PI & 8.61% with FLPI under normal voltage operation, and 35.46% with PI & 23.25% with FLPI under low voltage operation. With the recommended baseline of 75%, the FLPI model performance accuracy for the current THD control is found to be 76.75% along with mitigated switching transients, while that of PI is 64.54% without mitigated switching transients in the case of nonlinear operating behavior. Hence, FLPI model has proven to show a superior overall performance.

An Event-Driven Self-Clocked Digital Low-Dropout Regulator with Adaptive Frequency Control

Digital low-dropout (DLDO) is widely used for power management in the system-on-chip (SoC) because of its low-voltage operation and process scalability. However, conventional DLDOs suffer from the trade-off between transient response and power consumption of the DLDO and the clock generator. This paper proposes an event-driven self-clocked DLDO regulator. The proposed low quiescent current (IQ) event-driven adaptive frequency clock generator (EACG) adapts its frequency in different load conditions without a current sensor or complex compensation circuit for stable operation in the entire load range. The proposed DLDO does not need any external clocking signal and can maintain low output ripple and low power consumption in the steady-state. The clock-less transient detector (CLTD), consisting of two clock-independent transient detection paths, uses power more efficiently and improves the transient response significantly without sacrificing the power consumption. This work was fabricated in a 40 nm CMOS process with an 0.3 nF on-chip capacitor. The measurement results show that with the step load current between 1 mA and 60 mA, the proposed DLDO achieves a transient recovery time of 220 ns. The total IQ of the proposed DLDO is only 26 μA in steady-state, and it achieves stable operation in the entire load range.

Linear and symmetric synaptic weight update characteristics by controlling filament geometry in oxide/suboxide HfOx bilayer memristive device for neuromorphic computing

Memristive devices have been explored as electronic synaptic devices to mimic biological synapses for developing hardware-based neuromorphic computing systems. However, typical oxide memristive devices suffered from abrupt switching between high and low resistance states, which limits access to achieve various conductance states for analog synaptic devices. Here, we proposed an oxide/suboxide hafnium oxide bilayer memristive device by altering oxygen stoichiometry to demonstrate analog filamentary switching behavior. The bilayer device with Ti/HfO2/HfO2−x(oxygen-deficient)/Pt structure exhibited analog conductance states under a low voltage operation through controlling filament geometry as well as superior retention and endurance characteristics thanks to the robust nature of filament. A narrow cycle-to-cycle and device-to-device distribution were also demonstrated by the filament confinement in a limited region. The different concentrations of oxygen vacancies at each layer played a significant role in switching phenomena, as confirmed through X-ray photoelectron spectroscopy analysis. The analog weight update characteristics were found to strongly depend on the various conditions of voltage pulse parameters including its amplitude, width, and interval time. In particular, linear and symmetric weight updates for accurate learning and pattern recognition could be achieved by adopting incremental step pulse programming (ISPP) operation scheme which rendered a high-resolution dynamic range with linear and symmetry weight updates as a consequence of precisely controlled filament geometry. A two-layer perceptron neural network simulation with HfO2/HfO2−x synapses provided an 80% recognition accuracy for handwritten digits. The development of oxide/suboxide hafnium oxide memristive devices has the capacity to drive forward the development of efficient neuromorphic computing systems.

Regulating energy gap in Ir-based ionic complexes to generate near-infrared emissions: Application in solid-state light-emitting electrochemical cells

Solid-state light-emitting electrochemical cells (LECs) exhibit high potential for commercial electronics owing to their simple solution-processable device architectures, low-voltage operation, and compatibility with inert metal electrodes. However, the low device efficiency of most deep-red and near-infrared (NIR) LECs hinders their application (external quantum efficiency (EQE) < 1.00%). In this study, we demonstrate a simple method to tune the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of iridium-based ionic transition metal complexes (iTMCs) to generate NIR emissions. We investigate a series of cationic iridium complexes with small energy gaps, with 2,2′-bibenzo[d]thiazole fixed as N^N ligand moiety mainly controlling the LUMO energy level, changing a series of C^N ligands. All complexes exhibited deep red/NIR phosphorescence, and these combined devices provided emission peaks at 690–730 nm and were applied as components in LECs, exhibiting a maximum EQE of 1.78% in electroluminescence devices. Using a host–guest emission system with the iridium complex YIr as the host and complex TBBI as the guest, the highest EQE of LECs could be further enhanced to>2.34%, which is the highest value reported for NIR LECs.

An all-in-one graphene-based ionic actuator with fast switching response

Graphene, as a typical two-dimensional material is widely recognized for its excellent performance to application in many fields such as smart actuation systems. Here, an all-in-one graphene-based smart actuator has been developed for the first time. The graphene oxide film containing with ionic liquid are reduced on both sides via laser writing method. The smart actuator exhibits a promising actuation ability triggered by a low operation voltage of 0.8 V and delivers a deformation in fast switching response (10 Hz for one cycle) and excellent actuation stability. It means the new integrated graphene-based actuator has the potential for practical applications.

Skin‐Mountable Vibrotactile Stimulator Based on Laterally Multilayered Dielectric Elastomer Actuators (Adv. Funct. Mater. 23/2023)

Dielectric Elastomer Actuators In article number 2213589, Kilwon Cho and co-workers report a flexible and skin-mountable vibrotactile-stimulator based on thin lateral dielectric elastomer actuators. The actuator shows a significant actuation at low operating voltage because of a laterally aligned dielectric multilayer structure with short dielectric distance and a soft elastomer/ionic liquid composite. The vibrotactile-stimulator covers a broad perception frequency/amplitude range of human skin.

Investigation of Radiation Effect on Ge P-Channel Ferroelectric FET Memory

Zr-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO)-based germanium (Ge) p-channel ferroelectric FET (p-FeFET) memory devices with microwave annealing (MWA) followed by rapid thermal annealing (RTA) are employed as the platform to investigate the impact of γ-ray radiation on the device performance. With a radiation dose of 1 Mrad, the memory window (MW) degrades from 2.5 V to 2.0 V accompanied by the significantly increased off-state current. The deleterious radiation effect is ascribed to the susceptible quality of the interface between the gate dielectric and source/drain region due to exacerbated charge trapping for the Ge substrate. These trapped charges also screen the polarization charges after applying a voltage pulse and lead to increased read-after-write latency. Nevertheless, compared with the irradiated HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based FeFET memories in the literature, the Ge p-FeFETs in this work demonstrate competitive anti-radiation capability in terms of a large MW of 1.5 V even after 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> cycles by bipolar stress (±4 V/1μs) and desirable retention up to 10 years under low voltage operation.

Interfacial Layer Engineering in Sub-5-nm HZO: Enabling Low-Temperature Process, Low-Voltage Operation, and High Robustness

For low-voltage reliable operation of ferroelectric devices, the scaling of Hf <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{1}-\textit{x}}$</tex-math> </inline-formula> Zr <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\textit{x}}$</tex-math> </inline-formula> O <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{2}}$</tex-math> </inline-formula> (HZO) thickness ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{t}_{\text{HZO}}$</tex-math> </inline-formula> ) is important. Despite the importance of scaling, ferroelectricity degradation and increased process thermal budget hinder progress. In this work, we propose the use of an interfacial layer (IL) to mitigate these scaling issues and validate its effectiveness in thin <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{t}_{\text{HZO}}$</tex-math> </inline-formula> . Our findings demonstrate that IL can activate ferroelectricity below the critical temperature of ferroelectric HZO. Moreover, we report 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> polarization improvement, reduced operation voltage from 1.5 to 1.2 V, and substantially improved endurance with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt;$</tex-math> </inline-formula> 10 years of reliability, all based on experimental results. We believe this systematic work offers a simple yet efficient route toward HZO scaling in ferroelectric devices.

A 27-mW Ka-Band Complex Dielectric Sensor Chip With Readout and Reference Circuits Using 1.2-V Supply in 130-nm SiGe BiCMOS

The capability to sense the dielectric properties of liquids and tissues is valuable in many applications, because accurate assessment of the material composition can be made from the complex permittivity measurements. Laboratory-on-chip systems for continuous dielectric monitoring impose low-voltage and low-power operation on the circuits to enable long-term use without battery replacement. In addition, high level of integration is necessary to facilitate the implementation of 2-D sensor arrays. This letter presents the design and characterization of a SiGe BiCMOS capacitive sensing oscillator-based complex dielectric sensor chip at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band operating with a supply voltage of 1.2 and consuming 27 . The chip is integrated with readout circuits to provide simple dc outputs for easier processing and with reference circuits to serve as a tool to compensate for both the external and internal variations, which affect the sensor output. The experimental results show that different alcohols can be differentiated using the proposed sensor chip.

Dual-Gated Low Operating Voltage Metal Oxide Thin-Film Transistor for Highly Sensitive and Fast-Response Pressure Sensing Application

A solution-processed low operating voltage dual gated metal oxide thin film transistor (TFT) has been fabricated for pressure sensing applications. This device has been fabricated on a p-doped Si (p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -Si) using Li-Alumina (Li-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) as a bottom gate dielectric and SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin film as a semiconductor channel. Besides, piezoelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) thin film has been utilized as the top gate and dielectric on which external pressure has been applied. During bottom gate biasing, this TFT shows an n-channel behavior within 2 V operating voltage. Under such operation, the obtained value of threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ), carrier mobility (μ), and On/Off ratio of this device is 0.12 V, 2.60 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> .s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and 1.21 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> , respectively. After applying pressure under accumulation mode operation, drain current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> ) of the device reduces and the OFF current factor increases. Besides, the V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> of the device shifts towards higher positive gate voltage when external pressure has varied from 0.8 mbar to 1.6 bar. The drain current reduction, enhancement of OFF current factor, and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> shifting during the application of pressure of 1.6 bar are 50, 300, and 2000% respectively w.r.t their normal operation. The variation of all these parameters has two distinct regions with good linearity, one is < 80 mbar and the other is > 80 mbar, which is due to the saturation of orientation of the electric dipole of PVDF-HFP under a certain pressure range (< 80 mbar). Moreover, device response and recovery time are 90 and 5 ms respectively, indicating its prompt response to external pressure.

P‐155: Late‐News Poster: Low Voltage Operation a‐IGZO Thin Film Transistor Using by Thermal Oxidation Metal Oxide Insulator

We developed oxide thin‐film transistor using the tantalum oxide grown by thermal oxidation for the low voltage operation. Thermal oxidation was performed after the deposition of tantalum by sputtering as a gate electrode. The thermal grown tantalum oxide was analyzed by XPS. a‐IGZO TFT using a thermally grown tantalum oxide gate insulator operated at less than 2 V and compared it with aluminum oxide deposited by ALD.