C1 Size effects on the phase stability and switching properties of chemically synthesized HfO2 and Sb-based chalcogenide nanoparticles

The goal of Project C1 (2019-2023) is to analyze the effect of the three-dimensional confinement on the switching properties of individual resistively switching nanoparticles. As model compound for resistively switching metal oxides we will develop new synthetic routes to obtain HfO2 with variable structure and composition. As nanoparticulate phase change materials we will vary the composition of Sb-based materials to approach the conventional bonding regimes of metallic, covalent and ionic bonding and analyze the interplay of size and material composition on the crystallization features of the respective materials. Individual NPs will be integrated in lithographically fabricated nanogap devices (fabricated in Z4) as an approach for integrating chemically designed building blocks into nanoelectronic circuitry.

Following the synthetic routes, which have been developed in the first funding phase of the SFB, we will prepare metallic and resistively switching nanoparticles (NPs) by chemical synthesis. We will apply dip-pen nanolithography (DPN) and chemical e-beam lithography (C-EBL) to create surface patterns which are able to bind individual NPs and thereby to direct their assembly. Thereby we aim to control the particle topology as a key for integration of NPs into lithographically fabricated devices.

Project C1 introduces the development of solvothermal routes for the synthesis of metal oxide and chalcogenide nanoparticles in the sub-50 nm range and the investigation of the resistive switching properties of individual nanoparticles. As model systems for all three switching variants, we synthesize nanoparticles of selected oxides and higher chalcogenides, respectively. Electrical switching of individual particles is being carried out in-situ in a scanning electron microscope (SEM). We plan to systematically vary the particle size, and the defect concentration in terms of stoichiometry and doping. In the long term, successful candidates will be included in self-assembly techniques and surface patterning in order to produce long range ordered, registered arrays of switching cells.

Prof. Dr. rer. nat. U. Simon
Institut für Anorganische Chemie
RWTH Aachen University
Phone: +49 (0)241 80 94644
E-mail: ulrich.simon@ac.rwth-aachen.de