(Invited) Single-Molecule Sensor Arrays with Carbon Nanotube Transistors

Abstract

Electronic conduction in one dimension is uniquely sensitive to single point perturbations. As quasi-one-dimensional conductors, single-walled carbon nanotubes are ideal examples of this sensitivity, and they can be exploited as single-molecule sensors in air, liquid, or vacuum. Even in complex physiological solutions, dynamic biochemical activity has been monitored with single-bond and microsecond resolution. However, past work along these lines was achieved on individual devices with low success rates of 10-20%. Here, we describe simultaneous progress on three fronts that has produced large-scale arrays of single-molecule devices. First, precise control of catalytic chemical vapor deposition has dramatically increased our yield of usable single-nanotube devices across 4” substrates. Second, contamination control methods have reduced charge-trap fluctuations that previously disqualified many transistors from single-molecule sensing experiments. Thirdly, new surface modification protocols have brought predictability and control to single-molecule biofunctionalization of the nanotube surfaces. When combined, these techniques scale up single-molecule dynamic sensing from single devices to large arrays. New research directions with these arrays include massively parallel sensing applications such as drug discovery and DNA sequencing.