Tadashi Narusawa

Production of a microbeam of slow highly charged ions with a tapered glass capillary

The authors have developed a method to produce a microbeam of slow highly charged ions based on a self-organized charge-up inside a tapered glass capillary. A transmission of 8keV Ar8+ beam through the capillary 5cm long with 800∕24μm inlet/outlet inner diameters was observed stably for more than 1200s. The transmitted beam had the same size as the outlet with a beam density enhancement of approximately 10 and a divergence of ±5mrad. The initial beam was guided through a capillary tilted by as large as ±100mrad, and it still kept the incident charge.

Characterization of thick chromium-carbon and chromium-nitrogen films deposited by hollow cathode discharge☆

Both CrC and CrN films deposited by hollow cathode discharge show hard, wear-resistant and good anti-corrosion characteristics. The ranges of substrate temperature and molecular ratio of chromium atoms and reactant molecules (C2H2 and N2) arriving at the substrate were mapped, with Vickers microhardness as the parameter, for substrate bias voltages of 0 V and −50 V. The films were characterized using X-ray diffraction, transmission electron microscopy, electron diffraction, Auger electron spectroscopy and electron probe microanalysis. The hardness of these films did not decrease after vacuum annealing up to 820 °C but instead increased in some cases, the line broadening in X-ray diffraction becoming narrower. Comparison of the chemical compositions of these films by Auger electron spectroscopy and electron probe microanalysis gave linear correspondences.

Diffuse interface in Si (substrate)‐Au (evaporated film) system

When a gold film is vacuum evaporated at around 50 °C onto a clean surface of single‐crystal silicon substrate, the adhesion of the film to the substrate is very strong, which suggests that some chemical reaction has taken place at the interface. Present study by Auger electron spectroscopy (AES) concludes the occurrence of the above reaction which induces a diffuse interface region in order to relax (or minimize) the interface energy. For the relaxation of silicon (110) and (111) interfaces, at least 45 and 20 monolayers of gold are necessary, respectively. The phase of the thus‐formed interface is concluded to be similar to that of the nonequilibrium solid alloy obtained by quenching from a solid Si–Au eutectic liquid.

Ion irradiation in liquid of μm3 region for cell surgery

We present here a cell surgery scheme involving selective inactivation or disruption of cellular structures. Energetic ions are injected into a cell through a tapered glass capillary like a microinjection method. A slight but essential difference from microinjection is that a thin window is prepared at the outlet so that no liquid material can flow in or back through the outlet while still allowing energetic ions to penetrate into the cell. An ∼MeV He ion beam from such a capillary having 10μm outlet diameter inactivated a selected volume (∼μm3) of fluorescent molecules located in a HeLa cell nucleus.

Metallic state of Si in Si−noble−metal vapor−quenched alloys studied by Auger electron spectroscopy

Thin vapor−quenched films of Si−Au (Ag, Cu) alloys were studied by using Auger electron spectroscopy (AES). In these films, when the concentration of the noble metal was more than a critical value (∼70 at.%), the Si (LVV) Auger spectrum had double peaks at 90 and 95 eV; these peak energies were all the same for Si−Au, Si−Ag, and Si−Cu. However, with smaller noble−metal concentrations, the Si (LVV) spectrum was nothing but that of pure Si having a single peak at 92 eV. These results are explained by the statement that the double−peaked spectrum reflects the metallic state of Si quenched from the liquid state and some amount of metal is necessary to stabilize the metallic Si.

Swift heavy-ion irradiated active waveguides in Nd:YAG crystals: fabrication and laser generation

An Nd:YAG planar waveguide laser has been fabricated by ultra-low-fluence (2×10(12) cm(-2)) swift heavy-ion irradiation (60 MeV Ar(4+) ions). The appearance of the buried waveguiding has been associated with an increased refractive index layer as a consequence of the ion-induced electronic damage. Continuous-wave laser oscillations at 1064.2 nm have been observed from the waveguide under 808 nm optical excitation, with the absorbed pump power at threshold and laser slope efficiency close to 26 mW and 5.9%, respectively.

Formation of thick titanium carbide films by the hollow cathode discharge reactive deposition process

Abstract Thick titanium carbide films were successfully deposited on mild steel sheets using a hollow cathode discharge reactive deposition process. Methane, ethylene and acetylene were used as reactant gases during the titanium evaporation and the substrates were either negatively biased or grounded. The deposited films were characterized by microhardness measurements, X-ray diffraction, Auger electron spectroscopy and secondary ion mass spectrometry. The results are discussed with regard to deposition conditions and chemical composition.

Preferred orientations and microstructure of MgO films prepared by plasma-enhanced metalorganic chemical vapor deposition

Abstract NaCl-type magnesium oxide (MgO) films with (110) or (100) preferred orientation were prepared on glass substrate at 400°C by plasma-enhanced metalorganic chemical vapor deposition using Mg(C5H7O2)2 as a source material. The effect of deposition conditions, such as O2 flow rate, carrier gas N2 flow rate and total pressure during the deposition, on the preferred orientation of the MgO films were investigated. The total pressure during the deposition as well as the flow rate ratio of O2 to Mg source material were found to play a significant role in the preferred orientation of the films. (110)-oriented MgO films were obtained at low pressure under 0.15 Torr, while (100)-oriented MgO films were obtained at high pressure of 1.0 Torr, under the condition of a constant ratio of O2 to Mg source material. Rutherford backscattering and Auger electron spectra indicated that the O/Mg ratios of the films with (110) and (100) orientation were 0.97 and 1.61, respectively, and no impurities were contained in both the oriented films. Scanning electron micrographs showed that both films with (110) and (100) orientation were composed of closely packed columnar grains of diameter about 60 nm.

Auger spectroscopic observation of Si–Au mixed‐phase formation at low temperatures

When a Si crystal substrate is covered with evaporated Au and heated at relatively low temperatures (100–300 °C) in an oxidizing atmosphere, because of the Si–Au reaction at the interface, a SiO2 layer is readily formed over the Au layer. Present Auger spectroscopic study concludes that the reaction induces a Si–Au mixed phase that is almost identical with the Si–Au alloyed phase obtained by heat treatment in a high vacuum at temperatures well above the Si–Au eutectic point (370 °C). The Auger spectra of Si in both the mixed and alloyed phases differ obviously from that of the pure Si crystal.

Preparation and Properties of Single Crystal CuAlSe2 Film

Epitaxial CuAlSe2 film has been grown on the GaP(100) substrate by molecular beam epitaxy, and its optical and electrical properties have been characterized. The spectrum of optical reflectance suggests that the band gap of the film is about 2.7 eV, which agrees with that of the bulk material. The photoluminescence spectrum at 77 K showed no band edge emission, but only deep level-related emissions ranging from 520 nm to 870 nm. The CuAlSe2 sample exhibits n-type conductivity with the resistivity of 0.02 Ωcm, the carrier concentration of 4×1018 cm-3 and the mobility of 60 cm2V-1s-1.