SBIR Phase I: Chemical Detection And Identification With Nanocrossbar Arrays

This Small Business Innovation Research Phase I project aims to develop chemical detector and identification technology based on nanocrossbar arrays. The small dimensions of the nanojunctions enable a positive response to be triggered by only a few molecules. Selectivity of the junctions for different analytes is imparted by the chemical modification of the crossbar surfaces. Chemical sensing technologies often rely on changes in the bulk properties of a chemiresistor to transduce the presence of a molecular analyte into an electrical signal. As a result, these devices require a proportional amount of analyte molecules to affect a measureable change. By contrast, the nanocrossbar sensors directly measure the presence of a molecule by passing a small current through the junctions as the analyte passes. The small dimensions of the nanojunctions enable a positive response to be triggered by only a few molecules. Moreover, the tunneling mechanism responsible for changes in the sensors resistance leads to an exponential dependence on the analyte concentration. The small size, high sensitivity, low cost, and low power requirements make for a revolutionary advancement in chemical detection. The broader impact/commercial potential of this project is the introduction of the tunneling junctions as a circuit element and chemical transducer. The nanojunctions of the crossbar structures are ideal platforms for studying electron tunneling across nanometer dimension, an area crucial to understanding charge-transfer in molecular scale electronics. As nanotechnology strives to reduce the components of a circuit board to the nanodimensions, the nanocrossbar architectures provide a ready platform for connecting nanostructured memristors and molecular switches to electrical contacts. As a chemical transducer, the nanojunction sensors convert the presence of a few molecules into a measureable electrical signal. The unique combination of size, sensitivity, cost, and power requirements of the nanocrossbar sensors provides a chemical detection technology that can address applications which cannot be fulfilled with the conventional chemiresistor-based detectors. For example, remote-activated "sensor dust" can discretely monitor the air for explosives or contraband and nanocrossbar arrays can be embedded into conventional electronic circuits probing the environment. This versatility opens new market and greatly expands the potential of chemical sensing technology.