Carbon-derived micro- and nanostructures for chemical sensing

Carbon-derived micro- and nanostructures for chemical sensing in air and liquid environments have been developed. Gas sensing rectifiers comprised of micro-electrodes on diamond layers for detection of H/sub 2/, O/sub 2/, CO, and hydrocarbon gases have shown high sensitivity and fast response time over a very wide temperature range (>600/spl deg/C). Detection mechanisms of these microsensors have also been studied. A novel microelectronic gas sensor utilizing carbon nanotubes for hydrogen detection has also been developed. The sensor exhibits diode behavior at room temperature with drastic current changes in the presence of hydrogen. Also, diamond microelectrode arrays for electrochemical sensing in liquid media have been achieved and exhibited higher sensitivity than the conventional planar diamond film and other microprobes. Carbon-derived structures have broad practical applications for chemical sensing and have been demonstrated to operate at temperature, dynamic range, sensitivity, and radiation with far better performance than those based on silicon and other materials.