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Sarah Bedair — 2005-06 Fellow

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Single-chip integrated sensor systems are being developed for detection and identification of toxic, hazardous, or carcinogenic chemical vapors. Miniature, low-cost products incorporating these systems have numerous medical, environmental, and safety applications. Such systems are enabled by full on-chip integration of gas chemical microsensors with signal conditioning electronics. Current gas sensor technologies utilize discrete sensors that limit integration and lead to high cost, high power and bulky systems. The vision for a multi-modal integrated chemical nanosensor utilizes MicroElectroMechanical Systems (MEMS) technology to create arrays of sensors on a single chip, combined with CMOS circuitry to monitor the sensor environment, and to process and multiplex the numerous sensor output signals. Arrayed devices will provide multi-modal sensory information that can feed into algorithms for improved selectivity. The MEMS integration also enables device scaling for improved sensitivity.

A number of sensing modalities associated with a chemically sensitive material may be explored. Devices exploiting such modalities include chemi-resistors, chemFETs, mass (gravimetric) sensors, and calorimetric sensors. Toward the integrated gas nanosensor vision, this research project has three main goals:

1) incorporating multiple chemical sensing modalities onto a single device to obtain superior correlation between sensor data,

2) exploring methods to scale down resonant microstructures to improve the mass sensitivity and resolution of integrated gravimetric sensors, and

3) exploring a new capillary wicking approach to mass load chemically sensitive polymer onto gravimetric microsensors that is compatible with ink-jet polymer deposition.