Titanium and helium were simultaneously deposited on a titanium thin film sample to prepare a sample with nanocone structures. It was confirmed that the shape and size of the surface structure varied with the change of the amount of titanium deposition. The crystal structure after oxidation treatment in the air had an anatase structure. A combination of the anatase structure, and the increase in the

Raman scattering spectroscopy was applied to characterize polycrystalline germanium (Ge) on noncrystalline substrates fabricated by solid-phase crystallization and metal-induced crystallization (MIC) using copper (Cu) and tin (Sn) as the catalyzer. The subject was focused on the material for thin-film transistors in which the precursors, with the thickness of only 15nm, were deposited by sputtering

The strain dependence of stability and diffusion barrier height of the O vacancy in Si oxide is examined using the first-principles calculation. It is found that the stability and the diffusion barrier height increase as the oxide is compressed. The analysis shows that the diffusion barrier height is determined by the Si–Si distance of the O vacancy. Based on these results, the dielectric breakdown

We propose a fabrication process for a silicon on insulator (SOI) wafer with an extremely thick buried oxide (BOX) layer for custom micro-electro mechanical systems (MEMS) devices. A BOX layer is generally formed by thermal oxidation above 800 C. It is limited for this method to form an extremely thick layer of more than 10 μm. Thus, we attempted to deposit the BOX layer by chemical vapor deposition

Many dielectrics exhibit a (polarization) relaxation response when a time-varying electric field is applied. In some frequency bands, the amplitude of the polarization changes rapidly, with a significant dielectric loss; the maxima in the change rate are referred to as relaxation peaks. ZnO varistors exhibit a dielectric response with several relaxation peaks, but the relationship between the relaxation

An (AlGa)2O3 back barrier was employed for Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with a Si-implanted n-Ga2O3 channel layer. The insertion of the back barrier led to strong confinement of electrons in the channel layer, and a shallower pinch-off characteristic with shifting a threshold gate voltage by +8 V was attained for the MOSFET with the back barrier compared to the

We investigated the impact of selective thermal etching in a mixed hydrogen and ammonia atmosphere on the crystal quality and electrical characteristics of Ga- and N-polar AlGaN/GaN heterostructures. It was revealed that the etching rate of N-polar GaN is lower than that of Ga-polar GaN under our experimental conditions, and they showed a similar dependence on process temperature with almost the same

The barrier heights in Ti/ and Ni/n-SiC Schottky barrier diodes (SBDs) in a wide range of the donor density (N d = 2 1017–1 1019 cm−3) were investigated. The forward current–voltage characteristics in the heavily-doped SBDs (N d > 2 1017 cm−3) are described by the thermionic field emission (TFE) model, which includes an electron tunneling induced by the high electric field (> MV cm−1) at the Schottky

This paper presents a new multiple-time programmable (MTP) memory cell that features an n-well as the erasing gate and is implemented in a 16nm FinFET technology process. It is composed of slot contacts placed beside a metal gate for lateral coupling to the floating gate, while an n-well with a floating gate laid on top of it functions as erasing terminal. With adjusted slot contact length, a programming

In this paper, we experimentally examined the threshold voltage (V T) variability and the corner effects in gate-all-around p-type poly-Si junctionless (JL) nanowire (NW) and nanosheet (NS) transistors as a function of various effective channel width. The fabricated devices showed small V T variability characteristics even in poly-Si JL NW channel structure thanks to the improved quality of poly-Si

The variation of the electromechanical coupling factor of lead zirconate titanate (PZT) was studied using a piezoelectric PZT disk exposed to a 400MeV/n xenon beam. The resonant and antiresonant frequencies were measured in pairs by an impedance analyzer in situ manner. A systematic behavior of the pairs resulted in a decrease of the coupling factor. It was found that the coupling factor linearly decreased

Using a molecular engineering technique based on a tripodal triptycene-based supramolecular scaffold capable of precisely controlling molecular orientation on solid substrates, in combination with a time-domain thermoreflectance (TDTR) measurement technique, we evaluate thermal transport properties of a highly oriented long alkyl chain at the nanoscale. In the TDTR measurements, a 54nmthick film, in

Zinc oxide has attracted attention because of its unique properties that can be modified by doping. In this paper, we investigate the effects of oxygen addition to argon plasma during the sputtering of vanadium and aluminum co-doped zinc oxides. We find that reactive sputtering with oxygen is effective at reducing defects that degrade electrical conductivity and optical transmittance. Further, the

We elucidate the carrier transport mechanism from the p+-layer (metallic-conduction) to the n-layer (band-conduction) in a diamond p+–n junction, which is the basic structure of diamond devices. We fabricate Schottky–pn diodes containing p+–n junctions and analyze the temperature dependence of electrical properties in the forward bias region. At temperatures higher than the cryogenic region, free holes

Metal-organic frameworks, which are three-dimensional nanoporous materials composed of metal ions and organic ligands, have recently attracted significant attention as functional materials owing to their structural flexibility in the material design of uniform-size nanopores. In this study, basic investigations of the electrical properties of Cu3(btc)2 (btc; 1,3,5-benzenetricarboxylic acid) were carried

The van der Waals epitaxy (vdWE) of three-dimensional (3D) semiconductors on 2D materials has broad prospects for integrating the unique advantages of both. In this study, multilayer graphene (MLG) was synthesized by plasma enhanced chemical vapor deposition (PECVD) on sapphire and then flat GaN thin films were obtained through metal organic chemical vapor deposition (MOCVD) assisted by the sputtering

The penetration behavior of Ta, Nb, V, and Ti atoms into SiO2 substrate in the electric field are studied by the first-principles calculation, using the metal/SiO2 models. We found that the ionization charges of these atoms are extended over surrounding Si and O atoms and change with increasing the electric field reflecting the electron transfer from metal atoms to metal electrodes. These features

Nanographene synthesis, called hot mesh deposition (HMD) using pentacene molecules, H2 gas and heated W mesh, was investigated using Cu and Ni films prepared on quartz substrates. In HMD, the pentacene and H2 molecules were decomposed by the heated W mesh placed between the pentacene source and the substrate. In the case of Cu film, the peaks due to nanographene such as graphene nanoribbons (GNRs)

Organic thin-film transistors (OTFTs) are studied intensively for realizing practical applications of flexible or large-area circuits, but rapid degradation of OTFTs due to stress voltage or reaction with water vapor or oxygen in the air limits their lifetime. In order to analyze the cause of rapid bias-stress degradation, we propose a method that separates the cause of threshold voltage (V th) shift

The availability of low-cost hole transport materials (HTMs) that are easy to process is crucial for the eventual commercialization of perovskite solar cells (PSCs), as the commonly used HTM (Spiro-OmeTAD) is expensive, and its processing is complex. In this study, we synthesized an amorphous molecular material (termed as TPA-glass) from the condensation of 2-mexylamino-4-methylamino-6-(4-aminophenylamino)-1

The thermal stability of α-(Al x Ga1–x )2O3 films grown on c-plane sapphire substrates was investigated. The α-(Al x Ga1–x )2O3 epitaxial films grown by mist chemical vapor deposition were annealed at temperatures in the range of 600 C–1100 C in an atmospheric furnace, and then the crystal structures of the films were characterized using X-ray diffraction and transmission electron microscopy. When

Avalanche failure that occurs in circuits with inductive loads is an important issue facing silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs). Two mechanisms have been suggested for this failure: the activation of a parasitic bipolar junction transistor (BJT), and the intrinsic operation of SiC at extremely high temperatures. In this study, we propose a SPICE-based

The 300GHz band, which has a continuous 44GHz frequency band from 252 to 296GHz, was identified for wireless applications in WRC-19. The 300GHz band has the potential to achieve significantly higher transmission rates than conventional wireless communications. In addition, atmospheric attenuation is relatively low. Therefore, research on the 300GHz band has been attracting a lot of attention. Although

We present the experimental results on mapping characterization of the effects of photo-electrochemical (PEC) and inductive coupled plasma (ICP) etchings for both p-type and n-type GaN Schottky contacts by using scanning internal photoemission microscopy to clarify the current transport mechanism. The photoyield (Y) increased in the PEC etched regions by 4%–5% for the n-GaN, by 15% for the p-GaN samples

The effect of HfN multi charge trapping layers (CTLs) on the Hf-based metal/oxide/nitride/oxide/Si (MONOS) nonvolatile memory characteristics was investigated to improve the threshold voltage (V TH) controllability. The Hf-based MONOS structure with HfN1.3/HfN1.1/HfN1.3/HfN1.1 4-layer CTL realized precise control of flat-band voltage (V FB) and V TH compared to the Hf-based MONOS with HfN1.1 1-layer

An optical-disk-based system was developed to obtain images of blood cells for healthcare applications. The blood cells on the disk are scanned using a laser, and the intensity data of reflected or transmitted light from the sample are collected and reconstructed to form an image. Images of red and white blood cells were successfully obtained and both types of blood cells were visually distinguishable

We fabricated Tb3+-doped Li2O–Al2O3–B2O3 glasses using 6Li or n Li and 10B or 11B (6Li–10B glass, 6Li–11B glass, nLi–10B glass, and nLi–11B glass) to develop a new thermoluminescent (TL) material for neutron detection and investigated the TL properties of these glasses after X-ray, He ion, and neutron irradiation. TL glow peaks were observed at 350 and 550K after X-ray irradiation, at 390 and 550K

Multi-cations lead perovskite solar cells have shown higher performance than single-cation perovskite solar cells. This compositional engineering of perovskite material retains the optimum tolerance factor while allowing the tuning of the band gap in addition to the enhanced stability of cubic phase perovskite. However, no in-depth explanation has been provided on the relationship between crystal structure

The carrier transport characteristics of 1,4,8,11,15,18,22,25-octaalkylphthalocyanine (CnPcH2) thin films have been investigated by utilizing metal–insulator–semiconductor charge extraction by the linearly increasing voltage method. As the alkyl chain length of CnPcH2 increased from n=5 to 8, the estimated hole mobility decreased by almost one and a half order of magnitude in the range of 10−4 to 10−5

In this letter, we proposed an advanced dual-band detector based on the plasmonic response of patterned graphene integrated on a gold array. The photodetector shows ultra-high photoresponse performance in both visible light (0.4–0.7μm) and mid-infrared (4–14μm) light. The highest achievable responsivity of 2.7AW−1 is comparable with typical visible and mid-infrared photodetectors. The working wavelength

Characteristics of thin-film transistors (TFTs) with amorphous In2O3 (InO1.2) and carbon-doped In2O3 (InO1.16C0.04) channels by post-metallization annealing (PMA) process were investigated. The InO1.2 TFT changed from metallic to switching behavior after PMA at 200 C. In contrast, the InO1.16C0.04 TFT exhibited superior properties such as a threshold voltage (V th) of 3.2V and a high mobility of 20

We experimentally studied three types of group-IV-semiconductor quantum-dots (IV-QDs) of Si-, SiC-, and C-QDs in a thermal SiO2 layer that were fabricated using a very simple hot-ion implantation technique for Si+, double Si+/C+, and C+ into the SiO2 layer, respectively, to realize a different wavelength photoluminescence (PL) emission from near-IR to near-UV ranges. TEM analyses newly confirmed both

The reaction of the NO molecule at the 4H-SiC/SiO2 interface after dry oxidation is theoretically investigated on the basis of ab initio calculations. On the Si-face, the reaction of the NO molecule results in the dissociation of the C–C single bond and the formation of Si4–N bonds with the CO2 molecule. In contrast, the C=C double bond changes into the C–C bond with the formation of Si3–N bonds and

The correlation between current-voltage (I–V) characteristics and threading dislocations was evaluated using p-n junction diodes on a high-quality GaN substrate with an average threading dislocation density (TDD)≤4נ105cm−2 using the newly developed maskless 3D (M-3D) method. For the forward I–V characteristics, it was found that the “on” resistance (R on) increased as the number of dislocations in

The present study investigates the cyclic etching of TiO2 with CF polymer deposition and removal. We find that C4F8 plasma treatment forms a CF polymer deposition layer on the TiO2 and a modified TiO2 surface under the CF polymer layer. Subsequent O2 plasma treatment removes the CF polymer and the modified layer at the same time. This sequence is repeated. Accordingly, the TiO2 film is etched at a

The compact tunable single-mode microlaser is designed by combining the metal-optical Tamm state (metal-OTS) structure with the liquid crystal (LC) layer. Structural parameters are discussed for their corresponding effects on the tuning range and bandwidth of the transmission spectrum, etc. A range of 51nm around 1.55μm can be tuned as shown by the simulation for LC thickness of 1.4μm. The calculated

Cold atmospheric plasma (CAP) has gained increasing attention for its anticancer potential. CAP anticancer application is unique for its selective targeting of cancer cells than normal cells. These CAP effects are directly related to producing reactive oxygen species (ROS) and reactive nitrogen species in air and liquid environment. The ROS producing ability can vary greatly depending on the CAP source

For the purpose of developing In–Ga–Zn–O (IGZO) thin-film transistors (TFTs) on a flexible substrate, low-temperature (150 C) processed hydrogenated IGZO (IGZO:H) TFTs with anodize alumina gate insulator (Al2O3 GI) have been developed. We found that fluorination of the Al2O3 GI surface significantly improves field effect mobility (μ FE) and positive gate bias and temperature stress (PBTS) reliability

An on-chip noise monitor using a dual-mode analog to digital converter (ADC) is developed to detect the insertion of off-chip components as malicious attempts of power noise measurement attacks. A two-step sampling scheme selecting either synchronous or asynchronous clocking enables both real-time monitoring and high-resolution diagnosis of power supply noise, respectively. The monitor detects the

This paper presents a novel cluster validity index (CVI) engine based on global separation and local dispersion (GSLD) used to improve the accuracy and calculation efficiency of adaptive image clustering systems. The proposed GSLD engine can efficiently improve upon traditional GSLD calculation speed by making full leverage of temporary computation results obtained during the image clustering process

This paper presents an inductive impulse self-destruction circuit utilized in a sense-and-react IC-level countermeasure against physical attacks on a cryptographic processor. Triggered upon an alarm signal assertion by an integrated attack sensor, the proposed circuit instantaneously generates >10V high-voltage impulse to permanently destruct the cryptographic processor for enhancing tamper resiliency

Creating vertically aligned 2D nanostructures is a promising approach to achieving advanced electronic and optoelectronic materials. In this study, Mg2Si nanosheet bundles were synthesized by Ca atom extraction from CaSi2 microwalls grown on Si substrates via thermal annealing in a MgCl2/Mg mixed vapor. The nanosheet bundle structure was modified to compound nanosheet bundles from previously reported

In this work, the geometry effects on the energy band of the well-aligned silicon (Si) nanopillars (NPs) embedded in Si0.7Ge0.3 matrix fabricated by neutral beam etching are studied. We formulate and solve the Schrdinger equation with an effective mass approach in k space. The radius, separation, and shape effects on the energy band and density of states of the explored NPs are calculated and discussed

In quantum chemistry, it is important to estimate an energy gap between a ground state and an excited state of molecular Hamiltonians. In previous researches, it was necessary to measure the energy of the ground state and that of the excited state separately, and the energy gap was estimated from the subtraction between them. Here, we show a novel scheme to estimate such an energy gap in a more direct

We demonstrate a nondestructive way to determine the number of layers of hexagonal boron nitride (h-BN) by scattering-type scanning near-field optical microscopy (s-SNOM). The amplitude of s-SNOM near-field signals show a dependence on the number of h-BN layers, which can be explained by a finite dipole model. The layer number estimated by the s-SNOM is consistent with that observed by a transmission

Extended defects such as grain boundaries (GBs) promote serious damage for carrier transport in organic molecular solids. In this work, we studied electronic structures of specific examples of stacking-fault (SF) and GB defects in pentacene films by the first-principles calculation. We found that the SF decreases the carrier transfer for hole carriers, while it works as a scattering potential for electron

The impact of Sn on Si1-xGex through its thermal conductivity and phonon properties was investigated to develop an attractive material for thermoelectric devices. The Si-rich polycrystalline Si1-x-yGexSny alloy was synthesized by ball-milling technique. The as-synthesized alloy had substitutional Sn content of 1.60%, which it maintained as high as 0.54% after sintering at 1000 C. The thermal conductivity

We investigate the activation of Sn-V centers in diamond through ions implantation and the subsequent high pressure and high temperature (HPHT) treatment at 15GPa and 2300 C. Sn ions is implanted at fluences greater than 2נ1014 cm−2 by varying the acceleration voltage up to 180kV, which results in a Sn distribution with a uniform concentration of 1נ1020cm−3 down to a depth of 50nm from the surface

We demonstrate that photoluminescence in solid electrolytes is sensitive to the atomic structure of the defect complex that is decisive to the ionic conduction. We systematically measure the photoluminescence spectra of a typical solid oxide electrolyte, stabilized zirconia sintered pellets. Based on the comparison with the photoluminescence spectrum of a single crystal, we assign the broad long-lived

The current–voltage (I–V) characteristics of trigonal selenium (t-Se) nanowire (NW) crystals made via immersion in ethanol have been studied. A steep increase in current at the trap-filled limit voltage is observed in the I–V curve of t-Se NWs with a space-charge-limited current. From an analysis of the I–V characteristics based on a three-dimensional model, the trap concentration and trap energy are

A practicable solution to reduce the density of grain boundaries in metal thin films in order to improve their physical properties, and compatibility with nanoscale fabrications still remains a challenge for the thin film industry. We propose an alternative approach to the problem by using micron chevron-shaped laser beam (μCLB) annealing for rapid and selective growth of crystal grains in metal thin

Improved sensitivity of over 1 MVW−1, which exceeds that of conventional well-designed Schottky barrier diodes, was achieved in p-GaAs0.4Sb0.6/n-InAs nanowire backward diodes (NW BWDs) for low-power microwave energy harvesting at 2.4GHz under zero-bias. The antimony composition in the GaAsSb NWs was increased to 0.6 to form proper interband tunneling of the BWDs. A linear detected characteristic of

A simple vapor-based fabrication process for perovskite solar cells is developed and applied to the fabrication of inverted planar CH3NH3PbI3 (MAPbI3) perovskite solar cells. In this process, PbI2 film is deposited by vacuum evaporation on the hole transport layer (HTL), followed by converting it into the MAPbI3 phase by annealing in methylammonium iodide (MAI) vapor. Using the converted MAPbI3 films

Field effect mobility was improved in a 4H-SiC (0001) metal-oxide-semiconductor field-effect transistor with Ba diffusion into the gate oxide and NO passivation. The Ba diffusion process caused Ba interface passivation, which suppressed oxide surface roughening. Free carrier mobility and free carrier density were evaluated through Hall effect measurements using the Van der Pauw technique at room temperature

The study of nitrogen-vacancy (NV) centers in diamond are growing attractive in the application of quantum devices. Here, electrical control of NV charge state and defects induced by nitrogen ions implantation in diamond were investigated by transient photocapacitance (TPC) spectroscopy and photoluminescence (PL) spectroscopy. The experiments show that thresholds of 1.2eV appeared in TPC spectra are

The magnetic domain structure modulation in Ni wires deposited on a LiNbO3 substrate is observed during the application of a DC current or heating. A striped domain structure is formed in the Ni wires that is aligned perpendicular to the X-axis of the LiNbO3 substrate owing to the competition between magnetic shape anisotropy and uniaxial magnetic anisotropy from the heterojunction. We observe that

Nonvolatile flip-flop (NVFF) is an important component for implementing an energy-efficient logic large-scale integration (LSI) circuit that utilizes nonvolatile memory (NVM) function of magnetic tunnel junction (MTJ) devices. NVFF must be highly reliable in data store and restore operations for nonvolatile power gating. This study proposes an NVFF that can detect arbitrary errors occurring when storing

Open-circuit photovoltage decay from the steady state for the determination of bimolecular recombination constants has been studied in organic solar cells (OSCs) with three prototypical bulk heterojunctions including fullerene and non-fullerene acceptors. A simple theory for the determination of recombination constants from the initial decay rate of the open-circuit photovoltage was shown. The effective

This work demonstrates the fabrication of poly-(dimethylsiloxane) (PDMS)-based volume Bragg gratings (VBGs) by stitching of femtosecond laser filament. The refractive index change induced by femtosecond laser pulses is low (orders of 10−4 to 10−3) in PDMS. Therefore, the VBG thickness is the key parameter to fabricate high-efficiency VBGs in PDMS. With the intention of increasing diffraction efficiency

Analyzing the penetration of cosmetic/medical lotions and creams into the skin is important for evaluating their effectiveness. Hence, the penetration speed of liquids into chicken and pig skins was evaluated using a terahertz (THz) time-of-flight method. An arsenide-free disposable THz emitter comprising a silicon film on a sapphire substrate was developed for practical measurements using skin samples