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A p-type graphene–oxide–semiconductor (GOS) planar-type electron emission device holds promise as a photocathode with a high quantum efficiency (QE) for generating a high-speed modulated electron beam. We report the electron emission properties of a planar-type electron emission device based on a GOS structure using lightly doped p-type silicon as a substrate under laser light irradiation. The electron emission efficiency is 12% with and without laser light irradiation. The emission current shows a four-order of magnitude enhancement in the high field region compared to that in the dark, and a 0.3% QE is obtained without a negative electron affinity surface. This GOS device exhibits advanced photoassisted electron emission characteristics with high photosensitivity on the order of mA/W. The photoemission from the p-type GOS device shows a fast photoresponse with a rise time of less than 0.2 µs, which is the same as that of the current amplifier. By contrast, it shows a slow response of about 2.4 µs at the fall time, which is determined by the diffusion process of the photoexcited electrons in the bulk. The use of a highly doped p-type silicon substrate can be a practical route for further improvement.

This paper proposes a new operation method for an image pickup tube under high-temperature conditions. The landing energy of an electron beam is set at a value for the secondary electron yield above 1.0. The mesh electrode, which is located in front of the image plate, can act as a potential barrier and control the surface potential of the image plate in the balanced state, where secondary electron yield is 1.0. The polarity of signal charges can be also selected with the proposed method. These effects can suppress image degradation caused at high temperatures. We successfully demonstrated imaging operation around 100 °C.

Highly efficient electron emission of 48.5% was demonstrated by a graphene/oxide/semiconductor (GOS) structure. The main factors contributing to this performance were investigated by analyzing the ...

In this paper we report nanocrystalline ZnO thin films deposited by varying the Ga concentrations and atmosphere gas, onto the glass substrates using spray pyrolysis technique at 450 °C substrate temperature. After deposition Ga-doped ZnO thin films were annealed at temperature 420 °C in vacuum. The morphological, structural, optical and spectral properties of synthetized thin films have been characterized by scanning electron microscopy, X-ray diffraction, Raman analysis, UV–Vis spectrophotometry and spectrofluorimetry. The XRD result shows hexagonal structure with preferential orientation along the (0002) plane and the dependence of the values of the full-width at half-maximum of this peak on the nature of the gas used in the synthesis. Also, it is found that the optical bandgap can be increased by increasing the doping level. The fluorescence spectra of ZnO thin films with 1%, 2%, 3% and 5% concentrations of Ga demonstrate that these nanostructured thin films can produce reactive oxygen species (ROS) such as singlet oxygen under ultraviolet light. Nanocrystalline ZnO thin films in function of the Ga concentration provide the phosphorescence lifetime of the charge separated states up to 102 ms.

For the first time, in this work, we succeed in synthesizing in solution a novel supramolecular self-assembled zinc phthalocyanine (ZnPc) and N,N′-bis(3-pentyl)perylene- 3,4,9,10-bis(dicarboximide)...

In this work, morphological and physical properties of pyramid-like ZnO nanostructures fabricated on Sb-doped ZnO seeding films annealed under different atmospheres are extensively studied. The Sb-doped ZnO seeding films were first prepared by sol–gel spin coating technique onto glass substrate then annealed in nitrogen, air and argon followed by low-temperature hydrothermal process for ZnO nanostructures fabrication. The morphological results exhibit the growth of pyramid-like ZnO nanostructure with increasing density of the ZnO nanostructures. The crystal structure shows pyramid-like ZnO wurtzite hexagonal growth along the c-axis without any impurity phase. The growth of pyramid-like ZnO nanostructures is due to the high growth rate of (002) plane. Photoluminescence spectra exhibit the near-band-edge of all samples while the red emission appears in ZnO nanostructures after the hydrothermal process due to the imperfection in the crystal. The reflectance of ZnO nanostructures covers the visible region with the absorption edge of 375[Formula: see text]nm. The calculation shows the relevant energy band gaps in the range of 3.26–3.28[Formula: see text]eV. The difference in hydrothermally grown ZnO nanostructures is significantly affected by different annealing atmospheres.

A comparative analysis of the features of UV-stimulated emission (SE) of various disordered active materials based on ZnO crystallites for a random laser (RL) was carried out. The superlinear increase in the intensity of the UV photoluminescence (PL) band of polydisperse nano-micro-crystalline (PNMC) ZnO powder at a wavelength of λ = 387 nm and some narrowing of its halfwidth in the range of 20 ÷ 15 nm with increasing pump intensity indicates random lasing with incoherent feedback (FB). The properties of similar UV PL bands under the same conditions of a thin film containing hexagonal ZnO microdisks, as well as samples of monodisperse ZnO nanopowder with nanoparticle sizes of 100 nm, indicate stimulated radiation with coherent feedback. It is shown that, among the studied materials, PNMC ZnO powder with widely dispersed crystallites ranges in size from 50 nm to several microns, which in turn, consists of nanograins with dimensions of ~25 nm, is the most suitable for creating a random laser with incoherent feedback at room temperature. The dominant factor of UV SE in PNMC ZnO powder is radiation transitions under exciton–exciton scattering conditions. The possible mechanisms of this random emission with the continuous spectrum are discussed. The average optical gain coefficient αg at λ = 387 nm in this RL system is estimated as αg~150 cm−1.

The planar type electron emission devices using atomic layered materials of graphene and hexagonal boron nitride (h-BN) were developed to suppress inelastic electron scattering within the device structure. High emission efficiency of more than 40 % and high emission current density of more than 100 mA/cm2 were achieved by the suppression of the inelastic electron scattering within the topmost gate electrode using graphene,. In addition, highly monochromatic electron emission with an energy spread of 0.18 eV in the full width at half maximum were realized by the suppression of the inelastic electron scattering within the topmost gate electrode and insulating layer using the graphene/h-BN heterostructure. These results would lead to several practical applications of planar type electron emission devices.

We propose the scanning electron microscope (SEM) using the graphene-oxide-semiconductor type planar electron emission device as an electron source. Graphene/Oxide/Semiconductor (GOS) structure realizes very high electron emission efficiency of over 30 % and it can be operated in low vacuum condition and low applied voltage. Therefore, SEM using the GOS electron source can eliminate several condenser lenses from the electron optics which are needed in the conventional SEM due to the very small divergence angle of the electron beams emitted from the flat surface. In this study, we installed the GOS type electron source into the conventional SEM and successfully obtained the stable SEM image with a probe current of 20 pA without noise using GOS electron source. In addition, we found the optimal electron optics for the parallel electron beams with a very small divergence angle of approximately 0 degree by the simulation of the electron beam trajectory.

Electrical and optical properties of hydrothermally grown ZnO crystal, as well as structural changes at its surface have been investigated before and after irradiation by pulsed Nd:YAG laser. The spreading resistance measurements have shown a monotonous increase of conductivity by three orders of magnitude when the laser intensity I has been varied from zero to 290 MW/cm2. The PL spectra have revealed an increase of concentration of Zn interstitials at the surface after irradiation by I = 3.5 MW/cm2. Formation of Zn nanoparticles on the crystal surface has been observed at I > 290 MW/cm2. The study of surface structure at I = 315 MW/cm2 has shown that these Zn nanoparticles tend to transform into ZnO nanoparticles after an irradiation by more than 2 laser pulses. A theoretical model of thermal generation and redistribution of point defects has been elaborated to explain the origin of experimentally observed n-type conductivity. According to this model and experimental facts, the n-type conductivity originates from Zn interstitials, which are moved to the crystal surface by large temperature gradient during the laser processing. As a result, Zn-rich surface layer is formed and Zn nanoparticles grow, which are later oxidized into ZnO nanoparticles. We have shown a possibility to control the size distribution of these nanoparticles by choosing appropriate intensity and number of laser pulses.

Zinc oxide (ZnO) nano-rods has widely been investigated as a promising material for photo-catalysis, due to its high photocatalytic activity for the ambient gas molecules. Well-aligned ZnO nano-rods arrays were obtained by the two steps growth. Firstly, seeding layer deposition by RF magnetron sputtering, and secondly, nano-rods growth by hydrothermal processes were investigated. Moreover, after the samples were annealed at 450 °C, these samples were compared in crystalline characteristics and photo-electronic characteristics. The morphology of grown ZnO nano-rods were observed as the hexagonal nano-rods and XRD shows a (002) orientation in wurtzite crystals structure. Annealing processes shows a remarkable improvement of crystallinity. PL measurements showed a steep band edge emission and broad defect states emission and also fairly improvement in crystalline properties by the annealing process. The photoconductivity measurement could lead to investigate the photo-catalytic phenomena on the surface of ZnO nano-rods against the environmental gas molecules. The annealed samples showed a higher photo-conductivity and surface activity for the oxygen gas molecules comparing to the as grown samples.

Despite its importance in the real-world, manual (hand) dexterity is often ignored in medical-based virtual training environments that have traditionally focused on cognitive and affective skills development. Psychomotor (technical) skills, particularly those related to manual dexterity, are fundamental to various medical procedures and ignoring them in virtual based training tools can lead to a sub-optimal training experience. Here, we present a novel, consumer-level data glove that provides accurate user interactions involving the proximal and medial phalanges, interactions that are relevant in many manual dexterity tasks. We also outline how this novel data glove is being incorporated into an existing serious gaming platform for anesthesia training that currently focuses on cognitive and affective skills development only. The addition of psychomotor skills development through the adoption of simulated tactile feedback will provide a more complete serious gaming training platform.

In this preliminary study, we explore the use of a high-end data glove as a consumer-level hand exergame human interface device. Disorders affecting the musculoskeletal apparatus account for approximately 43 % of all workplace related injuries, leading to increasing claim costs and work absenteeism. Treatment includes unsupervised stretching and exercising with low adherence due to its monotonous and repetitive nature. Exergames, that is the use of games to elicit physical activity, provide engaging experiences that can help motive patients or workers into performing the exercises. Previous works using consumer-level technology have focused on image-based and open electronics 3D printed gloves that have shown the potential of exergames and motion capture as a tool to add immersion. In this paper, we present exergame that employs the Yamaha Data Glove (YDG) integrated to a computer- and robot-based exergame. The data glove allows controlling a virtual arcade crane in addition to interactive sessions with a social robot called ASUS Zenbo Junior. The preliminary quantitative and qualitative data suggest that motion capture data requires further processing and customization to tailor the experience to each user to improve usability and cognitive load affected by suitable tracking hand gestures. The exergame also requires additional cues to ease the experience and maintain users within a state flow.

In conventional downscaled Si transistors, the role of discrete dopants in nano-channels becomes critical; uniform high doping is desirable. Even in such highly-doped transistors, however, quantum dots formed by clusters of donors may work for single-electron tunneling (SET), and can be further assisted by co-doping. Here, we first analyze transport characteristics of co-doped Si nanowires by simulations, extending then the analysis to experiments on co-doped SOI-FETs with nanoscale channels. SET behavior is reported, and B-acceptors may contribute to the formation of tunnel barriers in such channels, suggesting a simple technique for Si SET devices.

Carbon Nanotube Field Effect Transistor (CNTFET) is cutting-edge technology where the demand for transistor scaling is increasing day by day industrially. Beyond 10 nm scaling of MOSFET is introducing several limitations like short channel effect, drain induced barrier lowering, less I on/off ratio etc. Instead of modifying the existing MOSFET technologies, recent new technologies are considered as future and as per prediction of the Global Market for carbon nanotubes report, CNTFET is going to make a severe impact in the semiconductor market. In this paper, first AC analysis is done by varying number of channels of GAA-CNTFET of Common Source Amplifier and results are shown in the form of a graph. Then AC analysis is performed by varying diameter of GAACNTFET and from the result of this analysis which maximum gain was obtained is chosen. Similarly, AC analysis is formed by varying oxide thickness (t ox ) and dielectric material (k ox ) and from the results of these analyses, the best-case gain is obtained for single stage, two stages, and three stages common source amplifier using CNTFET on 11 nm technology. In the frequency domain, it corresponds to 19.102 dB for single stage, 38.26 dB for two-stages and 56.34 dB for three stages.

The present study investigates Mg (0 &divide, 17.5 wt %), Cu (0 &divide, 21 wt %) and Ni (0 &divide, 20.2 wt %) dopants (M-doped) influence on photocatalytic activity of amorphous TiO2 thin films. Magnetron sputtering was used for the deposition of M-doped TiO2 thin films. According to SEM/EDS surface analysis, the magnetron sputtering technique allows making M-doped TiO2 thin films with high uniformity and high dopant dispersion. Photocatalysis efficiency analysis was set in oxalic acid under UV irradiation. In accordance with the TOC (total organic carbon) measurements followed by the apparent rate constant (kapp) results, the dopants&rsquo, concentration peak value was dopant-dependent, for Mg/TiO2, it is 0.9% (kapp&mdash, 0.01866 cm&minus, 1), for Cu/TiO2, it is 0.6% (kapp&mdash, 0.02221 cm&minus, 1), and for Ni/TiO2, it is 0.5% (kapp&mdash, 0.01317 cm&minus, 1). The obtained results clearly state that a concentration of dopants in TiO2 between 0.1% and 0.9% results in optimal photocatalytic activity.

This paper is based on a technique of Carbon Nanotube Field-Effect Transistors (CNTFET) for Arithmetic Logical Unit (ALU) using 10nm technology. For the past few decades, global demand for smaller dimension transistors with ultra-speed and low power consumption processor is a challenge for device designers. According to Moore’s law, the number of transistors on an integrated circuit (IC) doubles every two years. Traditional Si transistors, scaled down to its limit sub 10nm, suffer from short channel effects, direct tunneling from source to drain, drain induced barrier lowering, and hot carrier degradation. Hence device designer is looking for nano devices which can replace traditional Si. Carbon Nanotube Field Effect Transistors (CNTFET) are promising Nano device for the next generation. A parametric analysis has been performed for various measurements such as delay, power, and PDP by varying chirality vector. Here we discuss four Different configurations such as Single channel Single chirality (SCSC), Single Channel Dual chirality (SCDC), Double Channel Single Chirality (DCSC), Double Channel Dual chirality (DCDC). Based on the results it was observed that as the chirality vector increases delay decreases. It is also observed that the delay in Double channel configuration is less than in Single-channel configuration.

Photofield emission from SiGe nanoislands formed by molecular beam epitaxy (MBE) have been investigated. Two types of nanoislands, namely the domes and pyramids with different heights, have been addressed. It was found that the arrays of SiGe nanoislands exhibited a low onset voltage for field emission. The increase of emission current and the decrease of the curve slope in Fowler-Nordheim coordinates under green light illumination have been revealed. Electron field emission and photoemission from SiGe nanoislands have been explained based on the energy band diagram of Si-Ge heterostructure and some energy barriers have been determined.

Hydrogen generation through solar-driven photoelectrolysis of water is a promising technology for clean power supply. Zinc oxide (ZnO) is often applied to a photoelectrochemical (PEC) cells for water splitting, because ZnO has a favorable band edge that straddles the redox potential of photoelectrolysis in water. In addition, formation of ZnO nanostructure is attracting much attention, since the efficiency of PEC cell largely depends on a surface area of contacts. Here we report a modified hydrothermal method to prepare ZnOnanorods, whose structures can be controlled by changing preparation parameters. Our method includes seeding process by simple dip-coating technique, followed by post annealing process and hydrothermal growth process of ZnO nanostructures. The morphology of the grown ZnO depended on the concentration of the solvent used to form the seed layer formation, post-annealing temperature, and growth temperature. At the seed layer solvent concentration of 0.2 M, the ZnOnanorods were needle-like. At 0.9 M, hexagonal ZnOnanorods were obtained. We have successfully prepared hexagonalZnOnanorods by varying seed layer concentration at 0.9M, annealed at 150 °C for 2 h and grown at 120 °C for 1 h.