Search

Heat generation in integrated circuits (ICs) has become a severe issue, which limits the utilization of miniaturized semiconductor devices in high-density 3-D IC technologies. Herein, Al₂O₃ was doped in ZrO₂ thin films by plasma-enhanced atomic layer deposition (PEALD) to enhance their antiferroelectric (AFE) characteristics for highly reliable electrocaloric (EC) cooling applications. The cycling endurance in AFE behaviors of the Al:ZrO₂ thin films under a high electric field of 5 MV/cm was significantly improved because of the enlargement of the energy bandgap with high resistance in trap-induced leakage current. Hence, the reliability of the EC effect of the 1% Al:ZrO₂ thin film was examined with a negligible change in adiabatic temperature change (Δ T) of 2.6% after a cycling endurance test of 10⁶ cycles. With the competitive cycling reliabilities in AFE and EC behaviors, devices with optimized Al₂O₃-incorporated ZrO₂ thin films show significant potential for future nanoscale cooling systems in chip-level ICs.

Background Poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) (PEDOT:PSS) is a promising conductive polymer for the flexible piezoresistive pressure sensor. However, intrinsic hydrophilicity is detrimental to its structural stability under moisture. The present study aims to enhance piezoresistive pressure sensors' stability to achieve the highly-reliable electronic device applications. Method ITO/PEDOT:PSS/ITO piezoresistive pressure sensors with an interdigitated electrode (IDE) structure and different metallic interfacial layers were fabricated. Au layer was introduced between PEDOT:PSS sensing membrane and indium tin oxide (ITO) electrode as a reaction-inhibited interfacial coating of piezoresistive pressure sensors. Significant findings After a measurement time interval of 6 months, the interface reaction suppressed significantly, resulting in low sensitivity deviation (9.22%) and improved durability (400 cycles). The devices are completely sealed using polyethylene terephthalate packaging, avoiding humidity absorption in PEDOT:PSS films successfully. The packaged ITO/PEDOT:PSS/ITO piezoresistive pressure sensors with a double-sided 10-nm-thick Au interfacial layer is a promising candidate for use in highly reliable pressure sensing applications.

In this study, the antiferroelectric (AFE) and electrocaloric (EC) characteristics of lead-free titanium (Ti)-doped zirconia (ZrO2) thin films deposited via high-power impulse magnetron sputtering (HiPIMS) were investigated. The argon-to-oxygen ratio was initially optimized during deposition to obtain a more stoichiometric ZrO2 film for enhanced antiferroelectricity. Furthermore, enhanced crystallinity was achieved through the incorporation of Ti atoms into ZrO2 thin films as confirmed via grazing incidence X-ray diffraction and high-resolution transmission electron microscopy. For metal-insulator-metal capacitors with Ti-doped ZrO2 thin films, the AFE behaviors were significantly improved because of the excellent crystallinity of the tetragonal phase. Based on a fast polarization response and robust fatigue resistance under a 106-cycle endurance test, the EC effect was successfully explored, and an adiabatic temperature change (ΔT) of −14.8 K was realized. With competitive EC properties, Ti-doped ZrO2 thin films deposited via HiPIMS are proposed as promising candidates for use in future cooling systems.

Neurosurgical procedures often cause damage to the brain tissue at the periphery from surgical manipulations. Especially during retraction, a large amount of pressure could be applied on the brain surface, which can damage it, leading to brain herniation, which can be fatal for patients. To resolve this issue, we have developed a pressure sensor that can be used to monitor the applied pressure during surgery for intraoperative care. This device was tested on a rodent model to create a superficial surgically induced damage profile for three different applied pressures (30, 50, and 70 mmHg) and compared to a standard intracranial pressure monitoring system. Magnetic resonance imaging has been performed after surgical procedures to detect the herniation caused by applied pressure. To evaluate the damage to brain cells and tissue rupture, histological analysis was performed using hematoxylin and eosin staining. A scoring system was developed to understand the severity of the surgically induced brain injury, which will help neurosurgeons to limit the pressure to an optimum point without causing damage.

CF4 plasma treatment on n+-Si wafers as bottom electrodes (BEs) of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) metal-ferroelectric-metal (MFM) capacitors has been investigated in this study. Prior to the fabrication of MFM capacitors, comprehensive material analyses are administered to identify the incorporation of fluorine atoms into P(VDF-TrFE) copolymers, revealing an enrichment in C2HF3 (trifluoroethylene) bonds and an improvement in the crystallinity of the film. The P(VDF-TrFE) MFM capacitors with CF4-plasma-treated n+-Si wafers show a shallower charge trapping level of 0.154–0.226 eV extracted from the Frenkel–Poole (F–P) emission at 213–273 K for the BE injection compared to that for the top electrode (TE) injection, which is ascribed to the passivation of deep traps by the fluorine atoms that diffused from the n+-Si wafers. Thus, asymmetric remanent polarization and a negative internal bias field are obtained because of the significant increase in the β-phase at the bottom of the P(VDF-TrFE) films. With the CF4 plasma treatment for 1 min, the P(VDF-TrFE) MFM capacitors demonstrate a remanent polarization (2Pr) of 6.58 µC/cm2, a coercive electric field (Ec) of 0.47 MV/cm and stability for more than 3 × 104 cycles with negligible fatigue, making the fluorine-incorporated P(VDF-TrFE) copolymers suitable for future high-performance nonvolatile memory applications.

In the past decade, graphene has aroused worldwide academic passion in the electronics community, due to its unique two dimensional lattice structure and high mobility properties. Meanwhile, the utilization of graphene for next-generation nano-electronic materials is still under debate due to its intrinsic zero band gap nature. To meet the requirement of logic applications, diversified academic attempts have been carried out to modify its intrinsic band structure, such as doping, bilayer stacking, nano-patterning, or heterostructures. In this work, a tailor made strategy for graphene is proposed and experimentally demonstrated: a dimensionally anisotropic graphene based three terminal resistive random-access memory (RRAM). This device could be operated in two modes, which realized not only high carrier mobility (103 cm2 V−1 s−1) and low gate leakage in field effect mode, but also a high on–off ratio (107) and ultra-low off state current (1 pA) in resistive switching mode. This device also exhibits high reliability in logic data storage: long retention up to 8000 s, endurance of 400 DC operation cycles, and read immunity up to 1 million cycles. To guarantee the dimensional uniformity and high quality of the graphene, surface polishing and passivation techniques were carried out on Cu foil before graphene CVD synthesis. As demonstrated in this study, the current work paves the way for graphene toward practical logic and memory applications with high performance and low steady state power consumption.

The nervous system is a vital part of organisms to survive and it endows them with remarkable abilities, such as perception, recognition, regulation, learning, and decision-making, by intertwining myriad neurons. To realize such outstanding efficacies and functions, many artificial devices and systems have been investigated to emulate the operating principles of the nervous system. Here, an artificial reflex arc (ARA) and artificial pain modulation system (APMS) are proposed to imitate the unconscious behaviors of the spinal cord. Gd

In this paper, we demonstrate electrolyte-insulator-semiconductor devices for biochemical sensing applications prepared from ZnO and Ti-doped ZnO sensing membranes deposited on Si substrates by radio frequency sputtering. The structural, morphological, and compositional features of these deposited films with multitemperature annealing were studied using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. Sensitivity, linearity, hysteresis, and drift rate were measured to determine the sensing and reliability performance of all fabricated devices. Compared to the ZnO electrolyte-insulator-semiconductor (EIS), the Ti-doped ZnO EIS sensor annealed at 700 °C exhibits a higher sensitivity of 57.56 mV/pH, lower hysteresis of 2.79 mV, and lower drift rate of 0.29 mV/h. For Ti-doped ZnO, sensitivities of 3.62 mV/mM and 6.42 mV/mM were obtained for urea and glucose sensing, respectively. The improvements are owing to Ti-doping, which produces a rougher sensing surface, a well-crystallized grain structure, and thinner silicate and SiO2 at the silicon-oxide interface.

In this study, the effects of n-butylamine-modified graphite nanoflakes (BMGNFs) on the crystalline phase transition, ferroelectric behaviors, and piezoelectric energy harvesting properties of poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) copolymers are investigated. To confirm the blending of BMGNFs in P(VDF-TrFE), X-ray spectroscopy and Fourier-transform infrared spectroscopy (FTIR) are performed. Additionally, X-ray diffraction, FTIR, field-emission scanning electron microscopy, and atomic force microscopy are performed to analyze the crystallization of the polar β-phase of BMGNF-blended P(VDF-TrFE) copolymers. For P(VDF-TrFE) copolymers blended with pure graphite nanoflakes (GNFs), the crystallization of the polar β-phase is enhanced, but a high dielectric loss induced by the leakage current is clearly observed. The dielectric loss can be effectively reduced through the modification of GNFs by n-butylamine, which improves the remnant polarization and coercive electric field of metal-ferroelectric-semiconductor devices. Furthermore, the piezoelectric nanogenerators comprising BMGNF-blended P(VDF-TrFE) copolymers present a high open-circuit output voltage of 4.9 V and a high short-circuit output current of 4.5 μA for more than 500 times of cycling tests, exhibiting a high generating power density of 33.73 mW/m2 under a load resistance of 3 MΩ. Hence, the P(VDF-TrFE) copolymers blended with n-butylamine-modified GNFs show superior ferroelectric and piezoelectric behaviors, rendering them promising candidates for applications in future organic sensors and self-powered consumer electronics.

Traditional physical-based models have generally been used to model the resistive-switching behavior of resistive-switching memory (RSM). Recently, vacancy-based conduction-filament (CF) growth models have been used to model device characteristics of a wide range of RSM devices. However, few have focused on learning the other-device-parameter values (e.g., low-resistance state, high-resistance state, set voltage, and reset voltage) to compute the compliance-current (CC) value that controls the size of CF, which can influence the behavior of RSM devices. Additionally, traditional CF growth models are typically physical-based models, which can show accuracy limitations. Machine learning holds the promise of modeling vacancy-based CF growth by learning other-device-parameter values to compute the CC value with excellent accuracy via examples, bypassing the need to solve traditional physical-based equations. Here, we sidestep the accuracy issues by directly learning the relationship between other-device-parameter values to compute the CC values via a data-driven approach with high accuracy for test devices and various device types using machine learning. We perform the first modeling with machine-learned device parameters on aluminum-nitride-based RSM devices and are able to compute the CC values for nitrogen-vacancy-based CF growth using only a few RSM device parameters. This model may now allow the computation of accurate RSM device parameters for realistic device modeling.

This study investigated the effects of the bottom electrode (BE) on the resistive switching (RS) of silver programmable metallization cells (Ag-PMCs) with gadolinium oxide and aluminum oxide (Gd x O y /Al x O y ) solid electrolytes (SEs). The RS mechanisms of memories with different bottom electrodes were proposed based on the temperature dependence of the resistance at low resistance state (LRS) and current–voltage ( I–V ) fitting at high resistance state (HRS). The Schottky emission was dominant in the resistive switching of the memory with an iridium bottom electrode (Ir-BE), whereas in the memories with n + -Si and nickel (Ni) bottom electrodes, silver and both silver and nickel ions dominated the resistive switching, respectively. Additionally, the Ag-PMC with Ni-BE had a high resistance ratio of more than 10 7 as a result of the extremely low resistance of roughly 50 Ω at LRS. The Ag-PMCs with Gd x O y /Al x O y SEs and Ni-BE exhibited a retention behavior of more than 10 4 s and an endurance of more than 500 cycles with a resistance ratio of at least four orders of magnitude, which is promising for future high-density nonvolatile memory applications.

Piezoresistive pressure sensors have garnered significant attention because of their wide applications in automobiles, intelligent buildings, and biomedicine. For in vivo testing, the size of pressure sensors is a vital factor to monitor the pressure of specific portions of a human body. Therefore, the primary focus of this study is to miniaturize piezoresistive pressure sensors with graphene oxide (GO)-incorporated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composite films on a flexible substrate for biomedical applications. Prior to the fabrication of pressure sensors, a comprehensive material analysis was applied to identify the horizontal placement of GO flakes within the PEDOT:PSS copolymers, revealing a reduction in variable range hopping distance and an enhancement in carrier mobility. For devices scaled to 0.2 cm, the sensitivity of PEDOT:PSS pressure sensors was conspicuously decreased owing to the late response, which can be effectively solved by GO incorporation. Using technology computer-aided design simulations, the current crowded at the PEDOT:PSS film surface and in the vicinity of an indium-tin-oxide electrode corner was found to be responsible for the changes in piezoresistive behaviors of the scaled devices. The miniaturized flexible piezoresistive pressure sensors with PEDOT:PSS/GO composite films are capable of monitoring the brain pressure of intracranial surgery of a rat and discerning different styles of music for a potential application in hearing aids.

Solar-to-fuel conversion is an innovative concept for green energy, attracting many researchers to explore them. Solar-driven photocatalysts have become an essential solution to provide valuable chemicals like hydrogen, hydrocarbon, and ammonia. For sustainable stability under solar irradiation, titanium dioxide is regarded as an acceptable candidate, further showing excellent photocatalytic activity. Incorporating the photo-sensitizers, including noble metal nanoparticles and polymeric carbon-based material, can improve its photoresponse and facilitate the electron transfer and collection. In this study, we synthesized the graphitic carbon nitride (g-C3N4) nanosheet incorporated with high crystalline TiO2 nanofibers (NF) as 1D/2D heterostructure catalyst for photocatalytic water splitting. The microstructure, optical absorption, crystal structure, charge carrier dynamics, and specific surface area were characterized systematically. The low bandgap of 2D g-C3N4 nanosheets (NS) as a sensitizer improves the specific surface area and photo-response in the visible region as the incorporated amount increases. Because of the band structure difference between TiO2 and g-C3N4, constructing the heterojunction formation, the superior separation of electron-hole is observed. The detection of reactive oxygen species and photo-assisted Kelvin probe microscopy are conducted to investigates the possible charge migration. The highest photocatalytic hydrogen production rate of Pd/TiO2/g-C3N4 achieves 11.62 mmol&middot, h&minus, 1&middot, g&minus, 1 under xenon lamp irradiation.

A conductive polymeric film, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), is surface-modified by nitrogen plasma in order to enhance its piezoresistive characteristics. With an optimized 3 min nitrogen plasma surface modification, the piezoresistive sensitivity and response were significantly enhanced. Hall measurements and temperature-dependent conductance measurements are carried out to determine the electron-hopping behavior of nitrogen-plasma-modified PEDOT:PSS films, suppressing the horizontal carrier conducting pathway in the PEDOT:PSS piezoresistive pressure sensors. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy are applied to observe the PEDOT:PSS film surface after being modified with nitrogen plasma. The presence of sulfamate (SO3–NH2) and thiocyanate (S–C≡N) groups indicates a breaking of the electrostatic bonding between PEDOT and PSS and a modification of the conductive PEDOT conjugated chain. At the film surface, the formation of thiocyanate groups of ...

Characteristics of chemically-synthesized (CS) gold nanoparticle (Au-NP) nonvolatile memories (NVMs) with low-damage NH 3 plasma treatment on a tunneling oxide (TO) layer have been investigated. Although the dot density of CS Au-NPs is decreased, the programming efficiency of memories with optimized NH 3 plasma treatment condition is enhanced due to the formation of a trapezoid-like energy band diagram of the TO layer by nitrogen incorporation. With the extraction of relative permittivity and electron affinity of the TO layer, the capacitance-voltage ( C - V ) and programming behaviors of CS Au-NP memories with low-damage NH 3 plasma treatment on the TO layer are well-fitted by the TCAD (Technology Computer-Aided-Design) simulation. Further, the built-in electric field induced by the trapezoid-like energy band diagram of the TO layer can suppress the leakage current of the TO layer, thereby improving the data retention properties. The low-damage NH 3 plasma treatment that results in no plasma damage to the TO layer has been proposed to be the probable candidate for future NVM applications.

Layer-dependent solvent vapor annealing (LDSVA) treatment using dimethylformamide (DMF) vapor on specific layers of stacked poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) copolymers by metal-ferroelectric-metal (MFM) capacitors and nanogenerators was investigated in this study. Prior to the fabrication of the devices, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were performed to analyze the polarization of the crystalline β-phase in LDSVA-treated stacked P(VDF-TrFE) copolymers. After the LDSVA treatment on the top and bottom of the stacked films, the ferroelectric properties of P(VDF-TrFE) MFM capacitors became asymmetric. This can be confirmed via the bias electric field (Ebias) and non-switchable leakage current due to the non-uniform distribution of polarized dipoles. With an increase in LDSVA treatment time, the arrangement of polarized dipoles in stacked P(VDF-TrFE) copolymers was significantly enhanced, especially the samples with the treatment on the bottom of the stacked films, contributing to a large remnant polarization (2Pr) and a low coercive electric field (Ec) of the MFM capacitors. Additionally, the piezoelectric nanogenerators with LDSVA treatment on stacked P(VDF-TrFE) copolymers presented a large open-circuit output voltage of more than 4.02 V at 7 Hz under an applied force of 800 g, which is approximately 3 times larger than that of the samples without treatment. The LDSVA-treated stacked P(VDF-TrFE) copolymers with superior ferroelectric and nanogenerator behaviors exhibit good potential with regard to highly efficient energy harvesting applications.

Resistive-switching memory (RSM) is one of the most promising candidates for next-generation edge computing devices due to its excellent device performance. Currently, a number of experimental and modeling studies have been reported to understand the conduction behaviors. However, a complete physical picture that can describe the conduction behavior is still missing. Here, we present a conduction model that not only fully accounts for the rich conduction behaviors of RSM devices by harnessing a combination of electronic and thermal considerations via electron mobility and trap-depth and with excellent accuracy but also provides critical insight for continued design, optimization, and application. A physical model that is able to describe both the conduction and switching behaviors using only a single set of expressions is achieved. The proposed model reveals the role of temperature, mobility of electrons, and depth of traps, and allows accurate prediction of various set and reset processes obtained by an entirely new set of general current-limiting parameters.

Piezoelectric pressure sensing behaviors of high-density and low-damage CF4-plasma-treated indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) coated by poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) films have been investigated. The CF4 plasma treatment was performed on the IGZO channel by using an inductively coupled plasma (ICP) system with a quartz filter. Prior to the fabrication of devices, X-ray diffractometer (XRD) and atomic force microscopy (AFM) were applied to identify the enhancement in the crystallinity of P(VDF-TrFE) films on the plasma-fluorinated IGZO films. With the analyses of X-ray photoelectron spectroscopy (XPS), it is proved that the fluorine radicals reacted with the metal-oxygen bonds will increase the oxygen vacancies in IGZO films, contributing to an enhancement in field effect mobility (μFE) and drain current (IDS) of IGZO TFTs. Furthermore, the fluorine atoms diffused from the IGZO channel into the bottom SiO2 layer were confirmed by secondary ion-mass spectroscopy (SIMS), reducing the interfacial and oxide charges of the devices for a negative shift in threshold voltage (Vt). Under a 0.5-kg applied force press/release cyclic test, a 4.8-fold increase in drain current response of 1-min CF4-plasma-treated piezoelectric pressure sensors was optimized, because of the enhanced electrical behaviors of IGZO TFTs and an increase in aligned dipole moments of P(VDF-TrFE) copolymers. The promising results make the piezoelectric pressure sensors with high-density and low-damage CF4-plasma-treated IGZO TFTs coated by P(VDF-TrFE) copolymer suitable for future high-performance tactile sensing applications.

The high sensitivity of graphene to the surface condition of the gate dielectric layer and its poor van der Waals adhesion with a flexible substrate result in interfacial sliding and fracturing of graphene at low strains, making the successful utilization of pristine graphene (PG) in flexible electronics challenging. Here, we report a facile method for the fabrication of flexible graphene field effect transistors (F-GFETs) using sandwiched fluorinated graphene (FG). The “FG-PG-FG” sandwich structure shows a high optical transparency (>94%) with an average carrier mobility above 340 cm2/V·s, higher than that obtained when GO and Ion gel were used as gate dielectric materials on F-GFETs and a relatively low gate leakage current of ~160 pA. Furthermore, we observed a high mechanical stability, retaining >88% of the original current output against bending deformation of up to 6 mm and >77% after 200 bending cycles by applying a tensile strain of 1.56%, compared to the control sample. This improved performance is attributed to the fact that the sandwiched FG provides a good dielectric environment by tuning the C/F ratio, which tightly fixes the PG under strain. These findings provide a new route for the future development of graphene-based flexible electronics.

Memristors with rich interior dynamics of ion migration are promising for mimicking various biological synaptic functions in neuromorphic hardware systems. A graphene-based memristor shows an extremely low energy consumption of less than a femtojoule per spike, by taking advantage of weak surface van der Waals interaction of graphene. The device also shows an intriguing programmable metaplasticity property in which the synaptic plasticity depends on the history of the stimuli and yet allows rapid reconfiguration via an immediate stimulus. This graphene-based memristor could be a promising building block toward designing highly versatile and extremely energy efficient neuromorphic computing systems.

Sputtered titanium nitride (TiN) with a novel N2 ratio adjustment and rapid thermal annealing (RTA) treatment are proposed in order to optimize pH sensing performance of electrolyte-insulator-semiconductor (EIS) structure. Selection of this methodology, which can be easily applied into standard CMOS and DRAM technology, results from the fact that TiN is a well-verified material as a buffer or a barrier layer. It was concluded that pH sensitivity of the order of 60.5 mV/pH and linearity of 99.9% could be obtained for a TiN/SiO2 EIS structure treated with N2 ratio of 20% and RTA at 800 °C, which could be a good candidate in sensor applications. This performance is stable for more than two months. Higher surface roughness shown in atomic force microscope (AFM) analysis and high oxygen level in sputtering process shown in x-ray photo photoelectron spectroscopy (XPS) could be the reasons for the high sensitivity of the fabricated TiN sensing layer.

Multilevel resistive switching (RS) characteristics of silver programmable metallization cells (Ag-PMCs) with stacked SiO x /SiO2 solid electrolytes have been investigated. Combined with conventional high/low resistance states and additional two middle resistance states (MRS1/MRS2), a multilevel cell operation of stacked-solid-electrolyte Ag-PMCs is achieved and optimized by the film thickness. Furthermore, the RS mechanism at middle resistance states has been proposed to be locally discontinuous Ag conductive filament (Ag-CF) within the stacked solid electrolytes by examining the carrier transportation and two-frequency calibrated capacitance. The stacked silicon oxide layers can prevent the Ag-CF from regeneration during the multilevel retention test, contributing to the superior retention properties to more than $10^{4}$ s at 125 °C. In addition, a sequentially multilevel cycling test of more than $10^{3}$ times with a resistance ratio of two orders of magnitude between each resistance state is realized by the stacked-solid-electrolyte Ag-PMCs, suitable for future high-density nonvolatile memory applications.

Carrier injection and charge loss characteristics of nonvolatile memories with chemically-synthesized (CS) and vacuum-deposited (VD) gold nanoparticles (Au-NPs) have been investigated. Compared to CS counterparts, the memories with VD Au-NPs exhibit a higher dot density of 3.77 × 1011 cm−2, leading to a larger memory window. Further, the energy from valence-band edge to vacuum level (EVB_vac) of tunneling oxide for the samples with CS and VD Au-NPs is found to be 9.04 and 9.85 eV respectively. The small EVB_vac value of the memories with CS Au-NPs is resulted from the formation of a thin chemical oxide (SiOx) on thermally-grown SiO2 tunneling layer during the chemically synthesized process, contributing to a slow erasing behavior. Besides, the programming of the memories with VD Au-NPs is saturated at high gate bias, which has been well-explained by the electrons induced potential coupling between Au-NPs. Superior data retention property and high temperature dependence of charge loss are observed for the memories with CS Au-NPs, which can be ascribed to the thick tunneling oxide layer by the additional SiOx film.

Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF4 plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by the bandgap engineering of the gradually-fluorinated BO layer and the effective work function modulation of the Al gate. The Si–F complex in the BO layer was analyzed by X-ray photoelectron spectroscopy (XPS), while the depth of fluorine incorporation was verified using a secondary ion mass spectrometer (SIMS). In addition, the valence band modification of the fluorinated BO layer was examined by ultraviolet photoelectron spectroscopy (UPS) to support the bandgap engineering. The reactive power of the CF4 plasma treatment on the BO layer was modified to increase the electric field of the BO layer and raise the effective work function of the Al gate, leading to the hole-injection from the gate. The injected holes are trapped at the interface between the gold-nanoparticles (Au-NPs) and the tunneling oxide (TO) layer, resulting in superior data retention properties such as an extremely low charge loss of 5.7% at 104 s and a nearly negligible increase in charge loss at 85 °C of the CF4-plasma-treated Au-NP NVMs, which can be applied in highly reliable consumer electronics.

In this work, graphene nanodots have been fabricated and characterized as it has the potential for nanodevices application. Here we show non-volatile memory devices based on the capacitor structure by using graphene nanodots as the charge storage nodes. The graphene nanodots on silicon dioxide tunneling barrier were fabricated by etching the graphene with gold nanoparticles as self-aligned mask. Furthermore, different blocking oxide layer were also adopted to optimize the memory characteristics, including retention and operation speed. The memory of graphene nanodots with high-k blocking oxide layer shows higher flat-band voltage shift at low programming voltage, and excellent charge loss less than 12% after 104 sec, potentially provides a promising route for non-volatile memory application.

Bernal- and rhombohedral-stacked trilayer graphene (B- and r-TLG) on nickel (Ni) and iridium (Ir) films acting as bottom electrodes (BEs) of silver electrochemical metallization cells (Ag-EMCs) have been investigated in this study. Prior to the fabrication of the EMC devices, Raman mapping and atomic force microscopy are applied to identify the B- and r-TLG sheets, with the latter revealing a significant D peak and a rough surface for the Ir film. The Ag-EMCs with the stacked BE of r-TLG on the Ir film show a conductive mechanism of Schottky emission at the positive top electrode bias for both high- and low-resistance states that can be examined by the resistance change with the device area and are modulated by pulse bias operation. Thus, an effective electron barrier height of 0.262 eV at the r-TLG and Ir interface is obtained because of the conspicuous energy gap of r-TLG on the Ir film and the van der Waals (vdW) gap between the r-TLG and Ir contact metal. With the use of Ni instead of Ir contact metal, the Ag-EMCs with TLG BE demonstrate +0.3 V/-0.75 V operation voltages, more than 10

In this study, the cross-talk effects and the basic piezoresistive characteristics of gold nanoparticle (Au-NP) incorporated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) pressure sensing 2 × 2 arrays are investigated using a cross-point electrode (CPE) structure. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) mappings were carried out to confirm the incorporation of Au-NPs in the PEDOT:PSS films. A solution mixing process was employed to incorporate the nanoparticles. When the diameter of the Au-NPs incorporated in the PEDOT:PSS films (Au-NPs/PEDOT:PSS) was 20 nm, the piezoresistive pressure sensing 2 × 2 arrays were almost immune to cross-talk effects, which enhances the pressure sensing accuracy of the array. The Au-NPs render the PEDOT:PSS films more resilient. This is confirmed by the high plastic resistance values using a nanoindenter, which reduce the interference between the active and passive cells. When the size of the Au-NPs is more than 20 nm, a significant cross-talk effect is observed in the pressure sensing arrays as a result of the high conductivity of the Au-NPs/PEDOT:PSS films with large Au-NPs. With the incorporation of optimally sized Au-NPs, the PEDOT:PSS piezoresistive pressure sensing arrays can be promising candidates for future high-resolution fingerprint identification system with multiple-electrode array structures.

Graphene nanodiscs (GNDs), functionalized using NH3 plasma, as charge trapping sites (CTSs) for non-volatile memory applications have been investigated in this study. The fabrication process relies on the patterning of Au nanoparticles (Au-NPs), whose thicknesses are tuned to adjust the GND density and size upon etching. A GND density as high as 8 × 1011 cm−2 and a diameter of approximately 20 nm are achieved. The functionalization of GNDs by NH3 plasma creates N H+ functional groups that act as CTSs, as observed by Raman and Fourier transform infrared spectroscopy. This inherently enhances the density of CTSs in the GNDs, as a result, the memory window becomes more than 2.4 V and remains stable after 104 operating cycles. The charge loss is less than 10% for a 10-year data retention testing, making this low-temperature process suitable for low-cost non-volatile memory applications on flexible substrates.

A light-addressable potentiometric sensor (LAPS) with ceramic samarium oxide (Sm2O3)-sensing membrane treated by nitrogen plasma immersion ion implantation (PIII) has been proposed for chloride ion detection. For the pure Sm2O3-LAPS, a potassium ion sensitivity of 39.21 mV/pK is obtained. With the nitrogen PIII treatment on Sm2O3-sensing membrane, the N–O peak is observed by X-ray photoelectron spectroscopy, implying the formation of positive charges, (N-O)+ and (N-O-N)+, within the Sm2O3 film. The positive charges can attract the chloride ions to react with the surface sites of OH2+, achieving a superior chloride ion sensitivity of 36.17 mV/pCl for the Sm2O3-LAPS with nitrogen PIII treatment. The LAPS structure with ceramic Sm2O3-sensing membrane can be used for future biosensing applications, especially for the potassium and chloride ions detection in serum.

Multianalyte biosensors were fabricated with an Nb2O5 pH-sensitive membrane on silicon substrate in an EGFET structure. Incorporation of CF4 plasma treatment with an appropriate time of 15 s was found to improve material properties and enhance performance. Multiple material analyses including XRD, AFM and SIMS indicate that CF4 plasma treatment reduces dangling bonds and passivates defects by forming strong bonds. Results indicate that an Nb2O5-based EGFET exhibited good performance with a high degree of sensitivity, a low hysteresis voltage and a low drift rate. Overall sensing performance for various ions of Na+, K+, urea and glucose detection was also enhanced. Our research indicates that Nb2O5-based biosensors with CF4 treatment show promise for future industrial biosensing applications.

The characteristics of hybrid gadolinium oxide nanocrystal (Gd 2 O 3 -NC) and gadolinium oxide charge trapping (Gd 2 O 3 -CT) memories were investigated with different Gd 2 O 3 film thickness. By performing the rapid thermal annealing on Gd 2 O 3 films with different thickness, the Gd 2 O 3 -NCs with the diameter of 6–9 nm for charge storage, surrounded by the amorphous Gd 2 O 3 ( α -Gd 2 O 3 ) layer, were formed. The α -Gd 2 O 3 layer was considered to be the charge trapping layer, resulting in the large memory window of Gd 2 O 3 -NC/CT memories with thick Gd 2 O 3 film. The charge trapping energy level of the Gd 2 O 3 -NCs and α -Gd 2 O 3 layer was extracted to be 0.16 and 0.45 eV respectively by using the temperature-dependent retention measurement. Further, after a 10 6 program/erase cycling operation, the memory with thin Gd 2 O 3 film can be predicted to sustain a 94% memory window of the first cycling one while the memory with thick Gd 2 O 3 film suffered from a 30% charge loss because of the traps within the α -Gd 2 O 3 layer. The Gd 2 O 3 film thickness of 10 nm was optimized to exhibit superior performances of the Gd 2 O 3 -NC/CT memory, which can be applied into the nonvolatile memory.

For hybrid anion and cation ion sensing, an electrolyte–insulator–semiconductor (EIS) device with a samarium oxide (Sm 2 O 3 ) sensing membrane treated by nitrogen plasma immersion ion implantation (PIII) was proposed. The N + and N 2 + ions were implanted into the Sm 2 O 3 membranes to form the positive charges of N O and N O N bonds, which were investigated by the X-ray photoelectron spectroscopy (XPS). The observed positive charges were then correlated with the resulting anion and cation ion sensing performances. The EIS device with the pure Sm 2 O 3 membrane exhibited the mean potassium and calcium ion sensitivity of 36.71 mV/pK and 21.27 mV/pCa respectively because of the main surface sites of O − groups generated under the pH 8.0 Tris/HCl buffer solution. A high chloride ion sensitivity of 47.92 mV/pCl was obtained from the EIS device with nitrogen PIII treated Sm 2 O 3 membrane. This result is attributed to the reaction of OH 2 + group surface sites with chloride ions by the plasma induced positive charges within the membrane. The drift rate of less than 2.22 mV/h for the Sm 2 O 3 -EIS device was achieved and suitable for future biosensing use.

The paper reports samarium oxide as pH. sensing membrane on polysilicon combined with proper post deposition annealing for the extended-gate field-effect transistor (EGFET) application at the first time. It can be found that the high-k samarium oxide membrane annealed at 700 ºC could obtain high sensitivity, high linearity, low hysteresis voltage, and low drift rate due to improvements ofcrystalline structures. The high-k Sm2O3 sensing membrane shows great promise for future bio-medical device applications.