Increase In Breakdown Voltage Research Articles

An Improved 4H-SiCMESFET with Un-Doped and Recessed Area under the Gate for High Power Applications

In this work, a new structure of 4H-SiC MESFET with un-doped and recessed region under the gate (UR-MESFET) is reported. Channel of the proposed device is recessed into the p-buffer layer. The length and thickness of the un-doped area is equal to those of the recessed section. The un-doped section reduces peak electric field in the channel and then postpones breakdown phenomena. This can enhance breakdown voltage. Maximum breakdown voltage of the suggested transistor is about 138 V. This value is about 19% larger than that in the conventional (116 V). Recessed channel to the p-buffer increases saturated drain current significantly. Obtained results illustrate that saturated drain current of UR-MESFET is about 50% higher than that of the conventional device. Also, increasing breakdown voltage and drain current in the proposed device improves output power density about 90% compared to that in the conventional device. The suggested structure also reduces the gate-source and gate-drain capacitors significantly. The proposed transistor at best reduces the gate-source capacitor by 55% and reduces the gate-drain capacitor by 20% compared to the conventional structure. This makes the transistor perform better at high frequencies. As a result, it can be said that the proposed structure has better performance at high power and frequency than that of the conventional transistor.

Hybrid Multi-Graphene/Si Avalanche Transit Time <h-ATT> Terahertz Power Oscillator: Theoretical Reliability and Experimental Feasibility Studies

The prospects of Terahertz (0.3 THz-5.0 THz) power generation with laterally doped hybrid Graphene/Si (Single-Layer ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{S}_{\mathrm{ L}}\text{G}$ </tex-math></inline-formula> ), Bi-Layer ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{B}_{\mathrm{ L}}\text{G}$ </tex-math></inline-formula> ) and Multi-Layer ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{M}_{\mathrm{ L}}\text{G}$ </tex-math></inline-formula> )) Mixed Tunneling Avalanche Transit Time (GL-h-MITATT) oscillator is explored through an indigenously developed and experimentally verified self-consistent, non-linear, 2D-quantum drift diffusion simulator. The paper also reports the reliability study and feasibility of its development in details. The validity of the model is established by comparing experimental observation with simulation data for 0.2THz Si-oscillator under similar electrical operating conditions. The role of parasitic series resistance in top and side contact GL-MITATT oscillators are further studied. It is interesting to observe that compared to top-contact technology, side-contact technology results in lower contact resistance. With the increasing graphene layer in active region, the power output ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\sim }14\times 10^{9}$ </tex-math></inline-formula> Wm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> ), breakdown voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 8\text{V}$ </tex-math></inline-formula> ) and efficiency (~40%) increase significantly. The novelty of the study is in considering the laterally doped active region with top and side contact technology in exotic ATT devices and subsequent impact ionization & band-gap engineering boosting in performance enhancement. Additionally, the effect of series resistance is considered to obtain much reliable large-signal RF power data from the device under test. To the best of authors’ knowledge, this is the first report on DC and RF characterization of laterally doped Graphene/Si hybrid MITATT oscillators at THz region, by using an in-house simulator and corresponding fabrication feasibility.

The effects of multiwall carbon nanotubes on the electrical characteristics of ZnO-based composites

In this experimental work, the effects of multiwall carbon nanotubes (MWCNTs) on electrical characteristics of zinc oxide–MWCNT–high-density polyethylene composite varistors have been investigated. All the samples were made at the temperature of 130 °C and pressure of 60 MPa by the hot-press method. Results show that increasing zinc oxide content in the mixture increases breakdown voltage up to 170 V, where the highest nonlinear coefficient (α ~ 13) corresponds to the samples with 95 wt% of ZnO. Results with regard to the effects of MWCNT as an additive reveal that increasing its content from 1 to 2.5% in the composites, the breakdown voltage decreases to 50 V, but the highest nonlinear coefficient (~ 14) corresponds to the sample with 1.5% of MWCNT content. It is also revealed that, heat treatment of the sample at a constant temperature of 135 °C and different time intervals from 2 to 10 h, the sample with 6 h annealing time shows maximum breakdown voltages (Vb = 140 V) with the highest nonlinear coefficient (~ 14). Investigation of the potential barrier height of samples shows a complete consistency with the breakdown voltage variations. The results have been justified regarding XRD patterns and SEM micrographs of samples.

Impact of Implanted Edge Termination on Vertical β-Ga2O3 Schottky Barrier Diodes Under OFF-State Stressing

Both dc and OFF-state stress characteristics of vertical beta-gallium oxide (β-Ga <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> ) Schottky barrier diodes (SBDs) with or without ion-implanted edge termination (ET) were comparatively analyzed in this work. An implanted ET by He and Mg ions can effectively increase breakdown voltage (BV) from 0.5 to 1.0 and 1.5 kV, respectively, by sacrificing minimal forward characteristics. However, SBDs with ion ET exhibited a larger degradation than SBDs without ion ET after OFF-state stressing, especially for Mg ion-implanted ET, which caused more severe lattice damage at the edge of the anode by transmission electron microscopy (TEM) verification. The OFF-state characteristics were investigated by conventional measure/stress/measure (MSM) with reverse stress biases applied from -100 to -1000 V. The ion-implanted ET brings two effects on the device characteristics: 1) the increase of Schottky barrier height (φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> ) in both dc and OFF-state stress characteristics caused by the virtual gate-like effect and leading to an increased V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> and 2) the increase of R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,SP</sub> in the forward dc characteristics is attributed to the increase of anode resistance and lateral depletion.

Effect of a Single Threading Dislocation on Electrical and Single Photon Detection Characteristics of 4H-SiC Ultraviolet Avalanche Photodiodes**Supported by the National Key R&D Program of China under Grant No. 2016YFB0400902, the National Natural Science Foundation of China under Grant No. 61921005, and the Natural Science Foundation of Jiangsu Province under Grant No. BK20190302

We fabricated 4H-SiC ultraviolet avalanche photodiode (APD) arrays and systematically investigated the effect of threading dislocations on electrical and single photon detection characteristics of 4H-SiC APDs. Based on a statistical correlation study of individual device performance and structural defect mapping revealed by molten KOH etching, it is determined with high confidence level that even a single threading dislocation within APD active region would lead to apparent device performance degradation, including increase of dark current near breakdown voltage, premature breakdown and reduction of single photon detection efficiency at fixed dark count rate.

Vertical GaN-on-GaN Schottky Diodes as α-Particle Radiation Sensors.

Among the different semiconductors, GaN provides advantages over Si, SiC and GaAs in radiation hardness, resulting in researchers exploring the development of GaN-based radiation sensors to be used in particle physics, astronomic and nuclear science applications. Several reports have demonstrated the usefulness of GaN as an α-particle detector. Work in developing GaN-based radiation sensors are still evolving and GaN sensors have successfully detected α-particles, neutrons, ultraviolet rays, x-rays, electrons and γ-rays. This review elaborates on the design of a good radiation detector along with the state-of-the-art α-particle detectors using GaN. Successful improvement in the growth of GaN drift layers (DL) with 2 order of magnitude lower in charge carrier density (CCD) (7.6 × 1014/cm3) on low threading dislocation density (3.1 × 106/cm2) hydride vapor phase epitaxy (HVPE) grown free-standing GaN substrate, which helped ~3 orders of magnitude lower reverse leakage current (IR) with 3-times increase of reverse breakdown voltages. The highest reverse breakdown voltage of −2400 V was also realized from Schottky barrier diodes (SBDs) on a free-standing GaN substrate with 30 μm DL. The formation of thick depletion width (DW) with low CCD resulted in improving high-energy (5.48 MeV) α-particle detection with the charge collection efficiency (CCE) of 62% even at lower bias voltages (−20 V). The detectors also detected 5.48 MeV α-particle with CCE of 100% from SBDs with 30-μm DL at −750 V.

III–V nanowire MOSFETs with novel self-limiting Λ-ridge spacers for RF applications

We present a semi self-aligned processing scheme for III–V nanowire transistors with novel semiconductor spacers in the shape of Λ-ridges, utilising the effect of slow growth rate on {111}B facets. The addition of spacers relaxes the constraint on the perfect alignment of gate to contact areas to enable low overlap capacitances. The spacers give a field-plate effect that also helps reduce off-state and output conductance while increasing breakdown voltage. Microwave compatible devices with Lg = 32 nm showing fT = 75 GHz and fmax = 100 GHz are realized with the process, demonstrating matched performance to spacer-less devices but with relaxed scaling requirements.

Electrical characterization of 180 nm ATLASPix2 HV-CMOS monolithic prototypes for the High-Luminosity LHC

We report on the experimental study made on a successive prototype of High-Voltage Complementary Metal-Oxide-Semiconductor ATLASPix2 sensor for the tracking detector application, developed with 180 nm feature size. These sensors are to qualify mainly the peripheral data processing blocks (e.g. Command Decoder, Trigger Buffer, etc.). Over a decade, the monolithic pixelated sensors for a foreseen application to the ATLAS High-Luminosity LHC upgrade are being investigated as a viable option and a significant R&D progress made. It is a smaller version of 24× 36 pixelated sensor in comparison to the earlier generation of ATLASPix1 fabricated in both ams AG, Austria, and TSI Semiconductors, U.S.A. . While ams produced ATLASPix2 showed breakdown voltage ∼50 V in nonirradiated condition as it was seen on its predecessors ATLASpix1, TSI produced prototypes reported breakdown voltage greater than 100 V . The chosen wafer of MCz 20 Ω ⋅ cm P-type substrate resistivity can deplete a few tenths of μ m, where the process-driven surface damage can have a greater impact on device operating conditions before and after irradiation. In an aim to understand device intrinsic performance at the irradiated case, a dedicated neutron irradiation campaign has been made at Jožef Stefan Institute in Slovenia for different fluences. Characterizations have been performed at different temperatures after irradiation to analyze the leakage current and breakdown voltage before and after irradiation. TSI prototypes showed a breakdown voltage decrease (∼90 V) due to impact ionization and enhanced effective doping concentration. Results demonstrated for the neutron-irradiated devices up to the fluence of 2× 1015 neq/cm2 can still safely be operated at a voltage high enough to allow for high efficiency. Accelerated annealing steps were also made on selective irradiated ATLASPix2 samples, equivalent to more than two years of room-temperature annealing (at 20 °C), and they showed the reassuring expected breakdown voltage increase and damage constant rate α* (geometry dependent) decrease, driven by the beneficial annealing.

Breakdown process and fragmentation characteristics of anthracite subjected to high-voltage electrical pulses treatment

Enhanced coalbed methane recovery using high-voltage electrical pulses (HVEP) has been a popular research topic in recent years. However, the breakdown process and fragmentation characteristics of anthracite subjected to HVEP treatment remain unclear. This limits the popularization and application of this technology. In this work, Guizhou anthracite samples were subjected to electrical pulse tests with different breakdown voltages. This was performed using a high-frequency oscilloscope to obtain the voltage and current waveforms during coal breakdown. Furthermore, the pore structure and evolution of the microscopic cracks in the coal were analyzed via field emission-scanning electron microscopy, nuclear magnetic resonance, and X-ray computed tomography. Our results reveal that the breakdown of anthracite by the electrical pulse occurs mainly in two stages: thermal breakdown and electrical breakdown. Most of the energy stored in the capacitor is injected into the plasma channel of the coal in the electrical breakdown stage, during which the coal body displays apparent damage. Additional mesopores and macropores are produced as the breakdown voltage increases. The growth rate of seepage pores is significantly higher than that of adsorbed pores under a fixed breakdown voltage. In addition, the seepage pores of coal samples after HVEP treatment exhibit significant fractal characteristics. Meanwhile, several radial tensile microscopic cracks are formed inside the coal body. In general, the larger is the breakdown voltage, the more abundant are the tensile microscopic cracks. The mineral impurities in a coal body affect the expansion of the discharge channel. This, in turn, affects the direction of microscopic crack expansion.

Electrical Strength of Natural Esters Doped by Iron Nanopowder in a Hydrophobic Carbon Shell.

The paper presents the results of measurements of electrical strength of Midel 1204 natural ester doped with iron nanopowder in a hydrophobic carbon shell. The research was conducted for different concentrations of the dopant. The samples were prepared in the High Voltage Technique Laboratory. After mixing, they were tightly closed, and the first measurements were taken after 5 weeks of dissolution of the dopant in liquid. The tests were repeated after another 2 weeks and 3 weeks of dissolution of nanoparticles. An increase in both mean and maximum breakdown voltage was shown for the tested liquid mixtures. The concentration for which the value of electrical strength begins to decrease was indicated. It was also shown that a longer time of dissolution of nanoparticles causes an increase in the electric strength value for the tested samples.

Effect of Temperature on Insulation Properties of SF₆/N₂ Mixed Gas Under AC Voltage

The insulation properties of SF6/N2 mixed gas are important for the insulation design of high-voltage equipment such as gas-insulated switchgear (GIS) and gas-insulated transmission line (GIL). However, the influence of temperature on insulation performance of SF6/N2 under alternating current (ac) voltage is rarely studied. In this article, we did gas breakdown experiments with SF6/N2 mixed gas at temperatures changing from −50 °C to 100 °C. The experimental results indicate that the breakdown voltages of SF6/N2 mixed gas increase with the increase in temperature. In order to explain the phenomenon, the three-body attachment process in compressed SF6 is introduced to analyze the electron avalanche process affected by temperature. The streamer and leader discharge criteria are introduced to qualitatively explain the influence of temperature on the breakdown voltages. It is found that the streamer channel radius becomes larger at elevated temperatures, which causes the increase in breakdown voltage.

Experimental study on the effects of electrode materials on coal breaking by plasma

The extensively applied plasma technology boasts potential application prospects in the field of coal seam permeability enhancement. However, the effect of electrode materials on coal breaking by plasma (CBP) has not been reported. For this reason, the effects of four kinds of electrode materials, namely aluminum, copper, brass and stainless steel, on CBP were investigated by using a self-built CBP experimental system. The experimentally obtained statistics show that the sizes of coal fragments differ under the action of different electrodes. Specifically, the coal sample tends to be broken into small particles under the action of aluminum electrode, whereas the broken fragments generally have a diameter of larger than 15 mm under the action of brass electrode. The scanning electron microscopy results suggest that the different electrode materials correspond to different modes of crack initiation on coal surface. The results of liquid N2 adsorption show that the aluminum electrode exerts the poorest effect on improving micro-pores in coal, while the copper electrode achieves the best effect. Furthermore, the effects of electrode materials on the current and voltage waveforms at different voltages were analyzed by using a Rogowski coil and a HV test rod, and the effects of electrode materials on deposited energy generated by plasma in the coal were also discussed. The results indicate that at low voltages, the voltage and current waveforms under the action of four electrode materials differ obviously; in contrast, at high voltages, the voltage and current waveforms become almost identical. At the same voltage, the deposited energies formed by different electrode materials also differ due to the difference in breakdown voltages and current waveforms. The deposited energies formed by the aluminum electrode, the brass electrode and the stainless steel electrode inside the coal fall first and then rise with the increase of breakdown voltage, whereas that formed by the copper electrode goes up gradually with the increase of breakdown voltage. Based on the photograph of plasma discharge process shoot by a high-speed camera, the law of plasma propagation inside the coal was analyzed, and the effects of electrode materials on plasma development were discussed. A plasma streamer which is accompanied by dazzling white light and extremely high temperature is formed inside the coal at the moment of discharge, and it continuously expands outward as time passes by. The brightness degrees of plasma streamers formed under the action of electrode materials are different. Among the four electrode materials, the brass electrode forms the brightest light and generates the greatest energy.

Transformer Oil Dielectric Characteristics in Microwave Assisted Reconditioning Processes

Maintenance of transformer oil is needed to maintain the quality of power service. Thermal heating and filtering are the main ways to remove contaminants from the oil. In this research, a preliminary study was carried out using microwaves as thermal heaters in the reconditioning process of used transformer oil. The reconditioning process is carried out by filtering and thermal heating varies from temperatures of 40–100 °C using a microwave oven. Dielectric characteristics are shown by analyzing breakdown voltage, dielectric power loss, viscosity, and dc conductivity measurements. The amount of moisture content is also taken into account in measuring the level of thermal efficiency of the heater. Under the influence of microwaves, an increase in the characteristics of the dielectric strength in the form of an increase in breakdown voltage reaches 140.50%. Microwave heating is very good in reducing the water content in oil with a level of thermal efficiency reaching 25.55–40.40%. Removal of contaminants is better done by microwaves characterized by a decrease in the value of the dielectric power loss and dc conductivity at each treatment.

A novel SOI MESFET to spread the potential contours towards the drain

ABSTRACT This paper presents a new structure of Metal Semiconductor Field Effect Transistor (MESFET) for high power applications. One of the problems that we face in the design of the MESFET devices is that in most cases, the increase of breakdown voltage is accompanied by a decrease in the saturation drain current. Our aim to propose this structure is to improve these two parameters simultaneously. Using the insulator region under the sides of the gate (IR) and the hide field plate (HFP) in the buried oxide (BOX) are the fundamental solution for improving these parameters. We named the proposed structure as spread potential contours towards the drain MESFET (SPC-MESFET). By applying the proposed structure, the drain current and the breakdown voltage improve 20 and 27 percent compared to a conventional structure (C-MESFET), respectively. Therefore, the proposed device has a higher maximum power density than the C-MESFET structure. Also, this idea reduces the gate capacitance and thus the frequency characteristics such as cut off frequency (fT), maximum oscillation frequency (fmax), and Maximum Available Gain (MAG) improve in comparison with the C-MESFET structure.

Optical Investigation of Proton‐Irradiated Metal Organic Chemical Vapor Deposition AlGaN/GaN High‐Electron‐Mobility Transistor Structures

About 2 MeV proton numerical calculation damage indicates that a quasiflat profile is introduced into the GaN buffer layer of high‐electron‐mobility transistor (HEMT) templates. A previous transport study of such HEMT structures showed increased breakdown voltage and reduced GaN buffer layer leakage after proton irradiation. Hyperspectral electroluminescence measurements detected the emission band in the spectral region between 700 and 800 nm. This emission is assumed to be associated with the generation of trap levels responsible for the device failure. To obtain insights into the nature of radiation‐generated traps, detailed low‐temperature photoluminescence (PL) and cathodoluminescence (CL) experiments are conducted in a set of virgin and proton‐irradiated device structure templates. Both the PL and CL spectra show large intensity variations of all emission bands, in the spectral range between 330 and 890 nm, with increasing proton dosage. This is consistent with the introduction of compensating and/or nonradiative recombination centers in the GaN buffer layer. Luminescence measurements carried out under various excitation conditions show different recombination rates for emission bands observed near 420 and 550 nm, indicating different free carrier capture rates. Spectral analysis suggests that these two emission bands have different dependences on proton irradiation dosage, consistent with different chemical natures.

Electrical Characteristics of AlGaN/GaN High-Electron-Mobility Transistors Fabricated with a MgF2 Passivation Layer

We have demonstrated AlGaN/GaN high-electron-mobility transistors (HEMTs) fabricated with aMgF2 passivation layer. Upon MgF2 passivation using an e-beam evaporator, the HEMT showed a maximum drain saturation current of 508 mA/mm, a maximum transconductance of 136 mS/mm, a significantly reduced gate forward leakage current, a low gate reverse leakage current of 1.8 × 10−7 A/mm at gate bias voltage of −10 V, and an increased breakdown voltage of 563 V. This suggests that the MgF2 film is quite useful as a passivation layer for AlGaN/GaN HEMTs.

Vertical Leakage in GaN-on-Si Stacks Investigated by a Buffer Decomposition Experiment

We investigated the origin of vertical leakage and breakdown in GaN-on-Si epitaxial structures. In order to understand the role of the nucleation layer, AlGaN buffer, and C-doped GaN, we designed a sequential growth experiment. Specifically, we analyzed three different structures grown on silicon substrates: AlN/Si, AlGaN/AlN/Si, C:GaN/AlGaN/AlN/Si. The results demonstrate that: (i) the AlN layer grown on silicon has a breakdown field of 3.25 MV/cm, which further decreases with temperature. This value is much lower than that of highly-crystalline AlN, and the difference can be ascribed to the high density of vertical leakage paths like V-pits or threading dislocations. (ii) the AlN/Si structures show negative charge trapping, due to the injection of electrons from silicon to deep traps in AlN. (iii) adding AlGaN on top of AlN significantly reduces the defect density, thus resulting in a more uniform sample-to-sample leakage. (iv) a substantial increase in breakdown voltage is obtained only in the C:GaN/AlGaN/AlN/Si structure, that allows it to reach VBD > 800 V. (v) remarkably, during a vertical I–V sweep, the C:GaN/AlGaN/AlN/Si stack shows evidence for positive charge trapping. Holes from C:GaN are trapped at the GaN/AlGaN interface, thus bringing a positive charge storage in the buffer. For the first time, the results summarized in this paper clarify the contribution of each buffer layer to vertical leakage and breakdown.

Meandering Gate Edges for Breakdown Voltage Enhancement in AlGaN/GaN High Electron Mobility Transistors

Herein, a unique device‐design strategy is reported for increasing the breakdown voltage and hence Baliga figure of merit (BFOM) of III‐nitride high electron mobility transistors (HEMTs) by engineering the gate edge toward the drain. The breakdown of such devices with meandering gate‐drain access region (M‐HEMT) are found to be 62% more compared with that of conventional HEMT whereas the on‐resistance suffers by 76%, leading to an overall improvement in the BFOM for by 28%. The 3D technology computer‐aided design simulations show that the decrease in the peak electric field at the gate edge was responsible for increased breakdown voltage.

INFLUENCE OF ANODIC ALUMINA USED AS SEPARATING DIELECTRIC OF SILICON AVALANCHE LEDs ON DIODE CHARACTERISTICS

A study of the influence of the formation regimes of avalanche LEDs based on nanostructured silicon on the parameters of the formed devices, such as the light emission voltage and the stability of operation has been performed. These parameters are an important factor for the practical use of avalanche LEDs in the development of silicon photonics products, the progress of which is associated with the future of integrated electronics. For the first time, the technological operation of local through electrochemical anodizing of aluminum in various electrolytes for the formation of a separating dielectric of Schottky contacts is presented. The influence of the built-in electric charge in the separation dielectric of silicon avalanche LEDs on their current-voltage characteristics is studied. It was found that the built-in negative electric charge increases the breakdown voltage of the Schottky contact, which results in an increase of the light emission efficiency of the diode structures. An explanation of this effect is presented on the basis that the built-in negative electric charge inside the anode oxide also creates a space charge region in silicon, which helps to reduce the effect of the concentration of field lines at the edges of diode structures, performing the function of protecting the Schottky contact from edge effects as well as protective areas do. It has been established that the highest avalanche breakdown voltage is observed in diode structures with anodic oxide formed in an electrolyte based on an aqueous solution of phosphoric acid. An analysis of the characteristics of LEDs at different temperatures of silicon substrates showed an increase of breakdown voltage with increasing temperature, which is typical for avalanche breakdown during impact ionization. Stable light emission of the formed LEDs was demonstrated in a wide range of operating voltages (8–16 V). The use of silicon avalanche LEDs both as discrete devices and in integrated electronics in general has been discussed.

Solution-Processed Li2O-Al2O3/TiO2 Nanolaminate Stacks Containing Mobile Lithium Ions and with Increased Breakdown Voltages.

An aqueous solution approach has been utilized to prepare nanolaminates of TiO2 and ionically conductive Li2O-Al2O3 (LiAlO). This new approach utilizes low curing temperatures, resulting in fully oxidized films as demonstrated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The layered structures have been characterized by scanning electron microscopy, X-ray diffraction, and X-ray reflectivity. Incorporation of sufficiently thick (13 and 27 nm) ion blocking TiO2 layers into nanolaminate structures with LiAlO layers resulted in an increase in breakdown voltage by more than a factor of two, relative to LiAlO. Nanolaminate structures also preserve the large double layer capacitance of the ionically conductive layer. Increased breakdown strength coupled with large capacitances results in a doubling of ultimate charge storage capacity, illustrating how nanolaminates can be used to improve properties relevant for energy/charge storage applications.