Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 84: Novel Functional Materials I

HL 84.2: Vortrag

Donnerstag, 10. März 2016, 15:15–15:30, H17

Tunable Coulomb-oscillations in improved CoPt nanoparticle based field-effect transistors — •Hauke Lehmann, Svenja Willing, Mirjam Volkmann, and Christian Klinke — Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany

Metallic nanoparticles offer possibilities to build and improve basic electrical devices. The role of a semiconductor bandgap is adopted by the Coulomb energy gap due to the charging of the single particles capacities. Thus, it is required to keep the nanoparticles individualized by tunnel barriers, while a merging of the particles would render them metallic again.
We synthesize monodisperse CoPt nanoparticles by colloidal chemistry. Those particles are deposited via the Langmuir-Blodgett technique as highly-ordered homogeneous monolayers onto substrates with predefined gold electrodes. Additional structuring of the films yields stripes from individual nanoparticles. A local back-gate electrode is employed underneath the channel to influence the transport. This enables good electrostatic control over individually addressable devices without interferences from a dielectric capping layer. It has been found, that the gate electrode is most effective underneath a channel of comparable width, while the position of the gate electrode allows to shift the oscillations. Temperature and applied bias voltage in turn adjust the number of charge carriers in the system. Understanding the influences of the various parameters allows to precisely tailor the system’s properties to the needs of future applications.