Switching of Scattering Mechnaism by Gate Coupling Effect

Silicon nanowires (Si NW) offer unique transport properties and may combine differenttransport regimes within one device depending on the quality of the device. Here we report onthe fabrication of high-quality two-gated (back and front liquid-gated) Si NW FET structuresand their advanced transport properties. Voltages were applied to both gates in order to scanthrough different NW regions by conducting channel. A strong coupling effect between thefront liquid and back gate of the Si NW FET was revealed. Utilizing noise spectroscopy, wedemonstrate that the shift of the conducting channel from the top interface to the bulk of thenanowire switches the dominant mechanism of 1/f noise from a surface to a volume character.Investigation of transport under different back gate bias conditions allows the behavior ofcarriers under different scattering mechanisms within one device to be tracked. The observedcoupling effect leads to an increase of the FET transconductance accompanied by aconsiderable reduction of the channel noise. The effect was used to assist the recovery ofultra-small signals from the level below the detection limit of the liquid-gated Si NW FET. Theresults reflect broad perspectives for utilizing the coupling effect for a novel functionality ofadvanced nanoelectronic devices