Porous Tin Oxide Nanostructured Microspheres for Sensor Applications

Carlos J. Martinez and Steve Semancik

Process Measurements Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8362

There is a growing need to develop highly sensitive chemical sensors for applications such as military reconnaissance and toxic waste removal. A promising route for improving device performance is to use nanostructured materials (e.g. nanoparticles, nanowires, nanotubes) as sensor building blocks. We have sought to enhance the sensitivity of conductometric gas sensors through the design and fabrication of porous, three-dimensional tin oxide nanoparticle structures which have very high surface area. Films were fabricated via the self-assembly from solution of nanoparticle-decorated latex microspheres, which serve as sacrificial templates. Through heating, the latex microspheres were removed to reveal a 3-dimensional structure composed of interconnected spherical nanoparticle shells with porous ultra-thin walls. Sensor measurements were performed by depositing these films onto MEMS microsensor platforms with embedded inter-digitated electrodes and heaters. We report on film conductance changes measured at different temperatures, caused by exposure to test gases (CO, H2O, MeOH) in a dry air background. We also compare the performance of these high surface area films to films prepared through conventional routes such as CVD.

Presenting Author's information

Name: Carlos J. Martinez

Division: Process Measurements Division

Laboratory: Chemical Science and Technology Laboratory

Room and Building address: Room 307 Physics Building 221

Mail Stop: 8362

Telephone: (301) 975-4371

FAX: (301) 975-2643

email: cjm@nist.gov

Sigma Xi member?: No

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