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This paper reports deep levels in p-type 4H-SiC epilayers with and without electron irradiation by the current deep level transient spectroscopy. We also estimated time constants of hole capture by deep levels and discussed possibility that the deep levels behave as recombination centers.

The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H2O2) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H2O2 and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

We have characterized deep levels in as-grown and electron irradiated p-type 4H-SiC epitaxial layers by the current deep-level transient spectroscopy (I-DLTS) method. A part of the samples were irradiated with electrons in order to introduce defects. As a result, we found that electron irradiation to p-type 4H-SiC created complex defects including carbon vacancy or interstitial. Moreover, we found that observed deep levels are different between before and after annealing, and thus annealing may change structures of defects.

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The hydrogen desorption of Sn/MgH2 nanocomposite which is formed by ball milling of MgH2 and tin compounds (Sn, Sn(C4H9)4 or SnCl2), has been studied. The hydrogen desorption properties (desorption temperature and enthalpy of dehydriding) were significantly improved as a result of a Sn/MgH2 nanocomposite formation. TDS (thermal desorption spectrometry), TG (thermogravimetry) and DSC (differential scanning calorimeter) measurements exhibited the existence of at least two types of hydrogen species in the Sn/MgH2 nanocomposite resulting from ball milling of MgH2 with Sn; the one was hydrogen in the newly formed Sn/MgH2 nanocomposite and the other hydrogen derived from MgH2 remaining in Sn/MgH2.

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