[en] Crystallographic, electrical and optical characteristics are investigated for GaAs films grown by molecular beam epitaxy with gallium and hydrogen ion irradiation. Through growth experiments over a tungsten grating, ion irradiation is found to enhance surface atom migration. The optimum energy of H₂⁺ irradiation for the overgrowth is found to be 100 eV. However, all the ion irradiated films with the ion energy of 0.1-5 keV are highly resistive in spite of a Sn concentration of 3 x 10¹⁷ cm^-3. 77 K photoluminescence (PL) of as-grown films cannot be observed. It is concluded that ion irradiation gives rise to detrimental defects in the grown layer. These defects are produced by the momentum transfer of bombarding ions to a growing surface. (author)

[en] The characteristics of the electron avalanche of the self-quenching streamer mode in a cylindrical counter filled with an argon-methane-ethanol mixture were measured as functions of the concentration of ethanol (another quenching gas), the diameter of the anode wire and the incident X-ray energy. New systematics in generation of the streamer were obtained. (author)

[en] A multi-slit camera with an X-ray photodiode array has been developed to measure the electron temperature of a laser produced plasma. The fourth harmonic of Nd: glass laser output is irradiated on an aluminum plane target with a power density of 3x10¹⁴W/cm². The camera is set to view the plasma side. The profiles of X-ray intensity are obtained immediately. Using Abel inversion, the spatially resolved electron temperature distribution with 300 eV at the center is calculated by the absorption method assuming the Maxwellian distribution of free electrons. (author)

[en] Spatial investigations of potential fields of plasma waves excited by modulated infinite line sources in an inhomogeneous magneto-plasma are investigated. Distinctive mode patterns are obtained numerically. (author)

[en] The role of the gallium antisite defect, Ga_As, in the activation process of implanted Si in undoped GaAs was investigated by Hall effect and photoluminescence measurements. The activation efficiency increased with increase of the annealing temperature, but an efficiency reduction was observed above 900 deg C for 0 s hold time annealing and above 850 deg C for 20 min annealing. Moreover, p-type conversion took place above 900 deg C for 20 min annealing. It was found from photoluminescence measurements that at high temperatures the density of Ga_As was increased to reduce the activation efficiency and eventually to convert the material to p-type. It is pointed out that the density of Ga_As in semi-insulating GaAs must be low to attain high activation efficiency. It was also found that co-operative phenomena among C, Si and Ga that occupy arsenic sites appeared at rather high temperatures. (author)

[en] A new method for chemical analysis of surfaces by total-reflection-angle X-ray spectroscopy in RHEED experiments (RHEED-TRAXS) has been developed. When the X-ray take-off angle is set to be the critical angle for total reflection of the characteristic X-ray emitted from the deposited atoms on surfaces, the detection efficiency for the deposit becomes drastically higher owing to the refraction effect of the X-ray. This enhancement of surface sensitivity is demonstrated with Ag on Si(111). The smallest detectable amount of Ag is about 0.01 monolayer or less. This sensitivity is comparable to or higher than that of AES. (author)

[en] A spectrum similar to the optical absorption (OA) of X-irradiated LiF is observed by photoacoustic (PA) signal of microphone-detection method. A good agreement of the peak energy between the PA and the OA spectra is obtained for both F₂ and F₂⁺ bands. Similar thermal decay characteristic of the F₂ band in PA spectrum for powdered crystal to that in OA spectrum for single crystal indicates the usefulness of PAS for the study of TL process of powdered crystals. (author)

[en] A high velocity jet was formed by the Munroe-Neumann effect on a hemi-spherical target irradiated by a relativistic electron beam. The jet velocity and velocity multiplication were measured using N₂ laser shadowgraphies and a charge collector array. A jet efficiency of about 50% was measured by a calory meter. These values agreed with theoretical predictions. Experimental results indicated that a reduction of the velocity requirement for pellet ignition may be possible. (author)

[en] Compressed core density of a Cannonball target of inner pellet irradiation type at 10.6 μm laser wavelength was measured using spectrally resolved neon X-ray emission. The implosion simulations by HIMICO code agreed well with the experimental results and showed that the dominant force of implosion is hot electron driven ablation pressure. Comparison of the simulation and experimental results clarified that the core density was compressed to 200 mg/cc due to the truncation of high energy electrons. We show that the hot electron driven Cannonball target is a feasible scheme for high density compression at 10.6 μm CO₂ laser. (author)

[en] Characteristics of maskless ion beam assisted etching of Si have been investigated as a function of chlorine gas pressure. Focused Ga ion beam was irradiated on a Si substrate in chlorine gas atmosphere at a pressure ranging from 0 to 24 mTorr. The etching rate exhibited a maximum at a pressure of 8 mTorr, the value of which was about 5 times larger than the physical sputter etching rate, and decreased at higher chlorine gas pressure. At a pressure of 8 mTorr, the chlorine atom arrival rate was about 4 times larger than the Si removal rate. This ratio suggests that Si is mainly removed by forming volatile SiCl₄. (author)