Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Host: M. Koch
Friday, August 24, 2018, 1:00 pm
PC Seminar Room, G 2.06, Faradayweg 4
Experimental Semiconductor Physics group, Center for Nanotechnology and Nanomaterials, Walter Schottky Institut, Technical University of Munich
Networks of Hydrogen-Terminated Silicon Nanoparticles on Functionalized Surfaces
Electronic devices incorporating thin films of solution-processed crystalline nanoparticles (NPs) of semiconductor materials have been studied intensively in recent years as an alternative to bulk materials. Silicon is advantageous for use in the form of NPs, thanks to its abundance and non-toxicity. However, thin films of silicon NPs (Si NPs) with H-termination, required for adequate charge transport, are difficult to achieve due to NP agglomeration in solution. In this work, we explore the assembling of networks of H-terminated Si NPs bound to silicon dioxide surfaces functionalized with a monolayer of decyldiphosphonic acid molecules. We expect this method to provide a stable and patternable immobilization of very thin layers of Si NPs. Deposition of Si NPs can be realized via substrate immersion in Si NP dispersion, followed by annealing at 140°C. By comparison with control samples, our results indicate a beneficial effect of substrate functionalization and annealing for a stable attachment of Si NPs to the substrates. The electrical properties of the obtained Si NP networks are studied in a bottom-gate field-effect transistor configuration. We find that their floating-gate current-voltage characteristics can be described as a superposition of a linear and a super-linear term. Further, we study the conductivity as a function of coverage and estimate the corresponding field-effect carrier mobility and density.