Materials to Devices
In the Materials to Devices research group, we aim at integrating atomically precise carbon nanomaterials into functional devices. To this end, we are developing techniques and tools to reliably transfer these nanomaterials from their growth substrates to device platforms while preserving their structural and electronic properties. We develop protocols to characterize the structural quality of carbon nanomaterials and the transfer yield at all stages of their integration into devices based on Raman spectroscopy and scanning probe techniques. The Materials to Devices research line strategically connects the nanotech@surfaces Laboratory's expertise in the on-surface synthesis of carbon nanomaterials and that of our various device-oriented partners on nanoscale electronics.
Automated synthesis of low-dimensional carbon nanomaterials
At Empa, we have developed a fully automated ultra-high vacuum system for the scalable, rapid, and reproducible graphene nanoribbon (GNR) synthesis. Controlling the length and reaction yield during synthesis are not always critical for fundamental investigations of GNR properties, but they are essential for GNR incorporation into device structures as the GNRs must bridge electrical contact leads whose dimensions are limited by the resolution of e-beam lithography methods.
We are therefore developing and optimizing growth methods that lead to high reaction yields and long GNRs, and thus allow the properties of GNRs to be explored in multi-terminal devices. In view of the large-scale integration of GNRs and other low-dimensional carbon nanomaterials into devices, we also investigate pathways to scale up their production.
Substrate transfer and characterization
To explore the exciting properties of on-surface synthesized carbon nanomaterials in different device platforms, they need to be transferred from their metallic growth substrate to technologically relevant ones. We develop substrate transfer protocols based on wet and dry-transfer methods to integrate these materials in different device configurations.
In this context, we also develop characterization protocols and tools to evaluate the structural quality of the fabricated nanomaterials upon ambient exposure, substrate transfer, and device integration.
Raman spectroscopy is a key tool to assess the quality of carbon-based nanomaterials before and after substrate transfer and upon device integration. Beyond the characterization under ambient conditions (ex-situ) we also focus on developing in-situ (in ultra-high vacuum) Raman Spectroscopy tools and methods for characterization of spin-bearing GNRs (and other reactive structures), as well as the laser-induced photothermal synthesis of nanographenes.
Device integration
The Materials to Devices research line sets the foundation for our technology transfer activities. The scientific and technological developments achieved in this research topic allow the integration of graphene nanoribbons and other carbon-based nanomaterials into devices.
Device fabrication and (quantum) transport measurements are carried out by our device partners at Empa (Laboratory 405, Prof. Michel Calame and Prof. Mickael Perrin), at UC Berkeley (Prof. Jeffrey Bokor) and at TU Delft (Prof. Herre van der Zant). We closely collaborate on device fabrication and the improvement of contacting strategies to exploit carbon nanomaterials properties in different device configurations (https://www.empa.ch/web/s405/qd). One of our main goals is to explore spin-dependent quantum transport in carbon nanomaterials, which could lead to the development of an efficient platform for spintronics and second-generation quantum technologies.
Collaborations
