Signal-to-noise ratio in dual-gated silicon nanoribbon field-effect sensors

Recent studies on nanoscale field-effect sensors reveal the crucial importance of the low-frequency noise for determining the ultimate detection limit. In this letter, the 1/f-type noise of Si nanoribbon field-effect sensors is investigated. We demonstrate that the signal-to-noise ratio can be increased by almost two orders of magnitude if the nanoribbon is operated in an optimal gate voltage range. In this case, the additional noise contribution from the contact regions is minimized, and an accuracy of 0.5% of a pH shift in 1 Hz bandwidth can be reached. (C) 2011 American Institute of Physics. [doi:10.1063/1.3536674]