EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Randomly oriented nanowire networks, or nanonets (NNs), are interesting macrostructures as they combine properties at the nano-scale, from the nanowires, and the macro-scale, from the network. As such, they are easy to integrate into electrical devices. Moreover, they also present a high sensitivity and tolerance to defects or faults in network which is quite promising for sensing applications. In this work, we use Si NNs assembled by vacuum filtration of a nanowire dispersion. NNs are then integrated into electrical devices with remote protected electrodes using standard lithography processes: the channel of each transistor is open to interaction with an external medium (air, water, liquid to be tested…) while all metal lines and electrodes are kept away from the interaction by a protective layer. These devices, with channel lengths and width respectfully ranging from 5 to 100 µm and 10 to 100 µm, present typical transfer curves of p-type field-effect transistors (FETs), even when kept in interaction with water. These FETs exhibit a good modulation with a ratio between current at the On-state and the Off-state ranging $10^2$ to $10^5$, with best subthreshold slope of 0.48 V.dec$^{-1}$. This configuration allows us to study the effect of pH on the properties of FETs, but also to approach the electrical detection of DNA hybridization in liquid conditions.

Keywords
Si nanowire networks, Field-effect transistors, DNA electrical detection

Acknowledgments
This work has recieved funding from the EUH2020 RIA project Nanonets2Sense under grant agreement n°688329; from the EUH2020-ERA-NET project Convergence. It has benefited from the facilities and expertize of the OPE)N(RA characterization platform of FMNT(FR 2542, supported by CNRS, Grenoble INP,UGA), PTA (Upstream Technological Platform, co-operated by CNRS Renatech and CEA Grenoble, France).