Search

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 ...

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 ÷ 17.5 wt %), Cu (0 ÷ 21 wt %) and Ni (0 ÷ 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’ concentration peak value was dopant-dependent; for Mg/TiO2, it is 0.9% (kapp—0.01866 cm−1), for Cu/TiO2, it is 0.6% (kapp—0.02221 cm−1), and for Ni/TiO2, it is 0.5% (kapp—0.01317 cm−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.

A TiO2/Si hybrid photoelectrode (HPE) (photoanode) consisting of TiO2 and a Si n++p++nn++ photoelectrode, and a Pt-free counter photoelectrode (photocathode) consisting of Au or Ag clusters and a Si n++pp ++ junction were manufactured and investigated. TiO2 was deposited on the Si n++p++nn++ photoelectrode to widen the spectral selectivity from UV to visible light. The alternative Pt-free counter photoelectrodes were manufactured with a slightly different structure, where Au or Ag clusters were deposited on the n++ layer of the Si n++pp ++ junction. The photocurrent of the Si n++p++nn++ photoelectrode and the TiO2/Si HPE was measured using the Pt electrode or the Pt-free counter photoelectrodes. The analysis was carried out in the dark and under low-intensity UV light irradiation. The TiO2/Si HPE with the Pt-free counter photoelectrode (Ag clusters/Si n++p++nn++ junction) showed an increase of up to 74.2% in photocurrent compared with the Pt counter electrode. A deep-insight analysis for the new and simple design of the promising TiO2/Si HPE and the Pt-free counter photoelectrodes for hydrogen evolution from water was carried out.

A laser-induced oxidation method for the formation of a TiO2 layer on a Ti substrate was used. The TiO2 phase can be controlled by an Nd:YAG laser with fundamental frequency at an intensity I = 52.8 MW/cm2 and three different doses. Dose D1 = 3.1x1020 phot/cm2 forms a TiO2 layer in the anatase phase, which possesses the highest photocatalytic, antibacterial and adhesion properties. As the laser dose increases, the TiO2 layer thickness increases from 40 nm to 100 nm, but the photocatalytic decomposition reaction constant decreases. The observed super-linear increase of the TiO2 layer thickness with the laser dose is explained by the presence of positive feedback during the irradiation process. The temperature rises with increasing of the thickness due to the interference-caused decrease of the reflection coefficient. As the thickness increases, TiO2 on Ti structure adhesion decreases from 800 mN to 400 mN due to the formation of a layer with a mixture of phases. The colonization intensities of P. aeruginosa and S. epidermidis bacteria decrease more than tenfold after TiO2 formation. These results are explained by the partial transformation of the TiO2 layer, formed in the anatase phase at dose D1, into the rutile one at doses D2 and D3 due to a deficit of O atoms caused by the low diffusion of O atoms in Ti. According to our experiments and calculations, using the Wagner oxide model, the laser technology can be used to form crystalline structures with a monolayer precision.

The effect of UV Nd:YAG laser intensity on the conductivity and optical properties of hydrothermal ZnO crystal was studied. Three laser intensities characterizing the change of optical, electrical and morphological properties of the crystal have been revealed. The first is improvement of the crystal quality up to I 1 =3.2 MW/cm 2 . The second is at laser intensity higher than I 2 =249.0 MW/cm 2 when the formation of cracks takes place. The third I 3 =290.0 MW/cm 2 leads to the formation of “black ZnO”, which is caused by the emergence of Zn nanoparticles with size around 20 nm. At the same time conductivity of ZnO crystal continues to increase and exceeds the initial value by 277 times. The change of ZnO crystal optical and electrical properties is explained by generation, redistribution and agglomeration of Zn interstitials.

Al-doped ZnO thin films have been prepared by spray pyrolysis, which facilitates the incorporation of a higher percentage of dopant atoms. The vacuum thermally annealed at 420 °C temperature thin films have been characterized by X-ray diffraction (XRD), optical spectroscopy. Electrical conductivity and the Hall effect are investigated in the temperature interval (77–300) K. X-ray analysis results reveal that all the films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction (002) plane. Different characters of the temperature dependence of conductibility are observed in the Al-doped ZnO films vacuum thermally annealed at 420 °C temperature. In all cases, the conductivity, mobility carriers and carriers’ concentration of ZnO thin films obtained under Ar are higher than under O2 atmosphere, unless they are not doped. of your paper no longer than 300 words.

Electron transport through a few-donor cluster flanked by acceptors is studied by first-principles and semi-empirical simulations in gated Si-nanowire transistors with n + electrostatically-doped source/drain. Local density-of-states spectra are probed by electrical characteristics at room temperature for clarifying modifications induced by acceptor-atoms on the energy states of the few-donor cluster. It is found that acceptor-atoms located between the few-donor cluster and the leads mainly shift the cluster potential, introducing a minor distortion to its energy spectrum. The results change only weakly as the acceptor-atoms are moved towards the Si nanowire surface, and systematically depend on the number of acceptors.

The conduction band discontinuity between n-type Si substrates and anatase TiO2 films has been investigated. n-type Si substrates with three different dopant concentrations were used as a substrate for TiO2 thin-films: ND = 1015–16 cm−3 (as n-Si); ND = 1017–18 cm−3 (as n+-Si); ND = 1020–21 cm−3 (as n++-Si). The translation of X-ray photoelectron spectroscopy (XPS) results to an energy band diagram through the valence band offset (VBO) enables us to evaluate the conduction band discontinuities accurately: n-Si/TiO2—−0.22 eV, n+-Si/TiO2—−0.06 eV, and n++-Si/TiO2—+0.07 eV. Temperature–dependent current–voltage (I–V) characteristics were measured to evaluate the Fermi energy level (EF) of the TiO2 thin-films. Light transmittance was measured to evaluate the energy bandgap of the TiO2 thin-films. The band diagram of the n-type Si/TiO2 heterojunction was proposed. Deep-insight analysis of n-type Si/TiO2 was carried out on the basis of measured I–V characteristics.

For future broadband wireless links, we have designed a 300 GHz band traveling wave tube (TWT) with a folded waveguide fabricated by microelectromechanical systems (MEMS). The TWT operates at a beam voltage of 12 kV and a beam current of 8.3 mA. The classical large signal simulation code predicts the output power greater than 1 W and gain larger than 20 dB over the bandwidth from 280 to 300 GHz.

In this article, a field-induced electron emission from hydrogen (H)-terminated surface of heavily phosphorus (P)-doped diamond is discussed based on the barrier lowering model. Ultraviolet photoelectron spectroscopy suggested that an upward band bending of 1.45 eV existed at the surface of the diamond. A field emission characteristic as a function of the distance between an anode and diamond was measured to evaluate an average electric field in the vacuum. The barrier lowering model was introduced to estimate the reduction of the internal barrier due to the electric field at the diamond surface. The barrier lowering effect was confirmed from energies of emitted electrons, measured by combined ultraviolet photoelectron spectroscopy/field-induced electron spectroscopy (UPS/FES). As a result, it was shown that the electron emission from n-type diamond having NEA surface could be modulated by controlling a local electric field.

We studied the use of carbon-nanotube- (CNT)-based strain sensors as components of a textile-based, wearable sensing system for real-time motion detection. In the stretchable sensor, millimeter-long multiwalled CNTs (MWCNTs) are unidirectionally aligned and sandwiched between elastomer layers. We synthesized urethane resin to make the elastomer, which exhibits low elasticity and an affinity for human skin. The aligned CNT layer was formed by stacking CNT webs drawn from a spinnable CNT forest. The stretchable sensor can be stretched up to 200% and exhibits a short sensing delay of less than 15 ms. The gauge factor exceeds 10, which indicates high sensitivity. Moreover, the device is thin and as soft as human skin. The demonstrated flexibility and conformable nature make this material ideally suited for wearable sensors, specifically for a textile-based, wearable, real-time, human body motion-sensing application.

We have developed a highly sensitive, compact image sensor that comprises a field emitter array (FEA) and a high-gain avalanche-rushing amorphous photoconductor target, with the ultimate aim of developing an ultrahighly sensitive, compact, high-definition television camera. Double-gated FEs have an advantage of having a compact electron beam focusing system; however, image intensities reproduced by the sensor were nonuniform due to low electron beam current. Furthermore, the simulated electron beam current disagreed with the measured current. The electron beam current characteristics of two types of double-gated, Spindt-type FEs (both with improved electron beam current extraction) are discussed for possible use within the sensor: convex-structured and volcano-structured. A highly accurate simulation model of the image sensor using a double-gated, Spindt-type FE has been examined; the simulated electron beam currents extracted from the double-gated, Spindt-type FE are in agreement with the measured electron beam currents when the initial electron velocity is assumed, thus suggesting that the simulated anode current–anode voltage characteristic conforms to the measured one. For example, the electron beam currents extracted from the convex-structured and volcano-structured FEs when the focusing electrode is placed 0.2 $\mu \text{m}$ below the gate electrode opening at a focusing electrode voltage of 15 V are, respectively, 1.8 and 1.9 times larger than that extracted from the previously used FEs when the focusing electrode is stacked 1.5 $\mu \text{m}$ above the gate electrode. The results show potential for reducing the degradation of the uniformity of the reproduced image’s intensity, and show that the highly accurate simulation model of the sensor is valid to design the double-gated FEAs for the sensor.

A highly sensitive (at the picogram order) Al–doped–ZnO nanorods (AZNRs)–coated resonant microcantilever (MC) for carbon monoxide (CO) gas sensing, operable at ambient temperature and under humid condition was synthesized. The ZnO nanorods (ZNRs) were grown on the MC surface by using the hydrothermal method and doped by aluminum (Al). The sensitivities of un–doped and Al–doped ZnO nanorods for various CO gas concentrations were investigated by measuring the changes in the resonant frequencies and the Q–factor analysis of the vibrating MCs. The mechanisms of the remarkable enhancement of the sensitivity of the AZNRs–coated–microcantilever to CO were thoroughly investigated and discussed on the basis of energy gap between the highest occupied molecular orbital (HOMO)–Lowest occupied molecular orbital (LUMO) of AZNRs and CO, active surface area of AZNRs, and the interaction of water vapor on AZNRs surface with CO.

The oxygen plasma immersion ion implantation (O-PIII) method was used to form a TiO2 layer on a Ti substrate. The content of the anatase polycrystalline phase increased from 5.1% to 22.3% of the total TiO2 amount with a higher O+ ion dose. The oxygen ion doses were 3.6 × 1016 ions, 8.1 × 1016 ions, 1.26 × 1017 ions, for 1, 2, and 3 h, respectively, with ion energies of E ≈ 0.8 keV. The polycrystalline phases and morphology of the obtained films were characterized by XRD, FESEM, AFM, and Raman spectroscopy. The chemical bond analysis and layer-by-layer measurements for TiO2 layer thickness evaluation were performed by XPS. The photocatalytic decomposition reaction constants of a methylene blue solution increased from 3.2 × 10−3 min−1 to 4.2 × 10−3 min−1 under UV-A irradiation and the liquid free surface energy increased from 39.0 mJ/m2 to 49.5 mJ/m2 with a higher O-PIII treatment doses. These results were explained by the partial phase transition of the TiO2 layer from rutile to anatase. Thus, the increase in the O+ ions implantation dose into the Ti substrate invoked the reduction of material density from Ti (ρ = 4.506 g/cm3) through TiO2 rutile (4.23 g/cm3) to TiO2 anatase (3.78 g/cm3) phase.

Polycrystalline undoped and Al-doped ZnO thin films were deposited by spray pyrolysis using oxygen and argon atmospheres. The influence of postdeposition vacuum annealing on the structure, morphology and optical properties was studied by X-ray diffraction, atomic force microscopy and UV–VIS spectroscopy. The thermal vacuum annealing induces structural and morphological changes, especially in Al-doped ZnO thin films synthetized in oxygen atmosphere. Further on, the electrical conductivity in dependence of the nature of gas atmosphere and Al concentration is discussed.

The insensitivity of planar cathodes based on oxidized nanocrystalline silicon to ambient gas pressure is investigated. We demonstrate that the device operates normally even in the ambient gas pressure of 1 × 10−2 Pa. The result of the energy analysis of emitted electrons suggests that emitted electrons with less energy loss increase under hydrogen atmosphere.

We have proposed and developed a relatively low costed and simple constructed scanning electron microscope only with single objective lens but other convergent electron optics like condenser lenses using graphene-oxide-silicon planar type cold cathode (GOS) as an electron source. GOS has many superior aspects such as low voltage and low vacuum operation, stable emission, high emission current density, high efficiency against diode current, and so on. Especially, the quite low divergence of emitted electron beam from GOS have been expected to realize ideal parallel beam.