ZnO-Cu x O core-shell radial heterojunction nanowire arrays were fabricated by a straightforward approach which combine two simple, cost effective and large-scale preparation methods: (i) thermal oxidation in air of a zinc foil for obtaining ZnO nanowire arrays and (ii) radio frequency magnetron sputtering for covering the surface of the ZnO nanowires with a Cu x O thin film. The structural, compositional, morphological and optical properties of the high aspect ratio ZnO-Cu x O core-shell nanowire arrays were investigated. Individual ZnO-Cu x O core-shell nanowires were contacted with Pt electrodes by means of electron beam lithography technique, diode behaviour being demonstrated. Further it was found that these n-p radial heterojunction diodes based on single ZnO-Cu x O nanowires exhibit a change in the current under UV light illumination and therefore behaving as photodetectors.

The dependencies of the BiOi defect concentration on doping, irradiation fluence and particle type in p-type silicon diodes have been investigated. We evidenced that large data scattering occurs for fluences above 10 12 1 MeV neutrons/cm 2 , becoming significant larger for higher fluences. We show that the BiOi defect is metastable, with two configurations A and B, of which only A is detected by Deep Level Transient Spectroscopy and Thermally Stimulated Currents techniques. The defect' electrical activity is influenced by the inherent variations in ambient and procedural experimental conditions, resulting not only in a large scattering of the results coming from the same type of measurement but making any correlation between different types of experiments difficult. It is evidenced that the variations in [BiOi A ] are triggered by subjecting the samples to an excess of carriers, by either heating or an inherent short exposure to ambient light when manipulating the samples prior to experiments. It causes ~7h variations in both, the [BiOi A ] and in the effective space charge. The analyses of structural damage in a diode irradiated with 10 19 1 MeV neutrons/cm 2 revealed that the Si structure remains crystalline and vacancies and interstitials organize in parallel tracks normal to the Si-SiO2 interface.

CITATION liao, chuan (2021): The boron-oxygen (BiOi) defect complex induced by irradiation with 23 GeV protons in ptype epitaxial silicon diodes. TechRxiv. Preprint.

No abstract

Embedding electronic and optoelectronic devices in common, daily use objects is a fast developing field of research. New architectures are needed for migrating from the classic wafer- based substrates. Novel types of flexible PMMA/Au/Alq3/LiF/Al structures were obtained starting from electrospun polymer fibers. Thus, using an electrospinning process poly (methyl metacrylate) (PMMA) nanofibers were fabricated. A thin Au layer deposition rendered the fiber array conductive, this being further employed as the anode. The next steps consisted of the thermal evaporation of tris(8-hydroxyquinolinato) aluminum (Alq3) and aluminum deposition as the cathode. The Au covered PMMA nanofiber layer had a similar behavior with an Indium Tin Oxide (ITO) film i.e. low sheet resistance 10.6 Ω/sq and high transparency. The low electrode resistivities allow an electron drift mobility of about 10-6 cm2V-1s-1 at a low applied field, similar to the counterpart structures based on thin films. Concerning the relaxation processes in these structures, the Cole-Cole plots exhibit a slightly deformed semicircle, indicating a more complex equivalent circuit for the processes between metal electrodes and the active layer. This equivalent circuit includes reactance equivalent processes at the anode, cathode, in the active layer and most probably originates from the roughness of the metallic electrodes.