Thin films of boron carbide (B12+xC3-x) with carbon content of 0<x<1 have been successfully prepared by an pulsed ion-beam evaporation (IBE) method to optimize the thermoelectric properties. First, B12+xC3-x bulks with nominal carbon contents of 3-x = 2.0 to 3.0 were synthesized by a spark plasma sintering. Secondly, the B12+xC3-x, thin films were prepared on glass substrates by the IBE without substrate heating or sample annealing. From X-ray diffraction results, the films consisted of a B12+xC3-x, phase and lattice parameters of the phase were comparable to that of the target. It was concluded that B12+xC3-x, thin films with different carbon contents were successfully prepared at room temperature. Finally, thermoelectric properties of the thin films were measured. The B13.0C2.0 thin film exhibits the highest power factor at room temperature among B12+xC3-x, samples reported.

Summary form only given, as follows. YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (Y-123) high-T/sub c/ superconductor has excellent critical current density characteristics and thin films of Y-123 has been prepared by various methods. However, the deposition rate was limited and the increase in the deposition rate has been desired. A novel thin film deposition method has been developed, which is named as ion-beam evaporation (IBE). Extremely quick deposition rate can be characterized by this method which utilizes the high-density ablation plasma produced by a high power pulsed ion beam. In the present work, epitaxial Y-123 thin films have been successfully prepared by the IBE method. Deposition of Y-123 thin films has been carried out in a pulsed ion-beam generator ('ETIGO-II'). A voltage of 1 MV with the pulse width of /spl sim/50 ns was applied between the cathode and the anode. A polyethylene sheet (flashboard) was attached on the anode surface, worked as an H/sup +/ ion source. A Y-123 target was bombarded by a single shot of the ion beam. The ablation plasma was deposited on SrTiO/sub 3/ [100] substrates in vacuum (1 /spl times/ 10/sup -4/ Torr) and at room temperature. The thin films on the substrates were, annealed in flowing oxygen gas at 900/spl deg/C for 2 hours and 650/spl deg/C for 5 hours. The thin films were characterized with an X-ray diffractometer and a roughness tester. The XRD result for an annealed thin film indicated that all the peaks exactly correspond to the 001 reflections for a Y-123 phase. Since a [102] pole figure has four-fold symmetry, the Y-123 thin film was epitaxially grown on the substrate. The thickness of the Y-123 thin film was 0.3 /spl mu/m. From high-speed photographs of the ablation plasma, the plasma existed around the substrate for /spl sim/100 /spl mu/s. The instantaneous deposition rate of the film was 3 mm/s.

Summary form only given. Electron-beam-controlled switching experiments were performed using switch samples of quartz crystal and polycrystalline zinc selenide. The electron source (150 kV, 200 A, 2ns) was a very compact electron beam generator. The switch sample was set on a piece of 50 /spl Omega/ stripline to obtain a fast current rise. Connected with the stripline was a 3 m, 50 /spl Omega/ DC charged cable which discharges when the switch turns on. The current through the switch was observed downstream with a 50 /spl Omega/ terminated oscilloscope. For the quartz crystals, the authors used samples to 80 /spl mu/m in thickness and induced the current through the sample by the electron beam. With a charging voltage of 3 kV, very fast temporal response (less than 1 ns) was obtained with the quartz samples. For the polycrystalline ZnSe samples, switch current was induced through samples 0.9 mm in thickness. The current transients of ZnSe were found to be on the order of 10 ns and the development of the switch resistance after the electron beam pulse was observed to be exponential.