Anomalous Transient Current in Nonuniform Semiconductors

Nonequilibrium processes in semiconductors are considered with highly nonuniform initial densities of charge carriers. It is shown that there exist such distributions of charge densities under which the electric current through a sample displays quite abnormal behaviour flowing against the applied voltage. The appearance of this negative electric current is a transient phenomenon occurring at the initial stage of the process. After this anomalous negative fluctuation, the electric current becomes normal, i.e. positive as soon as the charge density becomes more uniform. Several possibilities for the practical usage of this effect are suggested.Comment: 1 file, 11 pages, RevTex, no figure

Pulse ion annealing of silicon layers with silver nanoparticles formed by ion implantation

© 2020 Elsevier Ltd The paper presents the results of Si surface modification created by implantation with Ag+ ions at energy of 30 keV, current density of 8 μA/cm2 for various doses from 6.0·1015 to 7.5·1016 ion/cm2 and annealed by powerful beam pulses (C+, H+) of nanosecond duration. Scanning electron microscopy and optical reflection measurements showed that after ion implantation an amorphous a-Si layer on the surface of c-Si substrates with Ag nanoparticles was formed. Followed pulse ion beam annealing of sample obtained at lowest dose of 6.0·1015 ion/cm2 leads to melting and recrystallization of the Si surface layer with segregation of Ag nanoparticles. For samples implanted with doses higher than 2.5·1016 ion/cm2 after annealing an epitaxial cellular breakdown structures are fabricated on the Si surface decorated at the cell boundaries by Ag nanoparticles

High-intensity pulsed ion beam treatment of amorphous iron-based metal alloy

© 2020 Published under licence by IOP Publishing Ltd. The results of intense pulsed ion beam (IPIB) treatment of the soft magnetic amorphous alloy of a FINEMET-type are presented. Foil produced from the alloy was irradiated with short (about 100 ns) pulses of carbon ions and protons with energy of up to 300 keV and an energy density of up to 7 J/cm2. X-ray diffraction, Mössbauer spectroscopy and magnetic measurements were used to investigate structural and magnetic properties of irradiated foils. It is shown that the foil remains intact after the treatment, and the crystal structure still amorphous. Spontaneous magnetization vector is found to lie almost along perpendicular to the foil plane after irradiation, whereas for the initial amorphous foil it belongs to the plane. The magnetic properties of the foil undergo changes: the coercive force decreases, the saturation induction increases slightly, and the magnetization curve has shallower slope