Accession Number : ADA270625


Title :   Investigation of the Sensitivity, Selectivity, and Reversibility of the Chemically-Sensitive Field-Effect Transistor (CHEMFET) to Detect Nitrogen Dioxide, Dimethyl Methylphosphonate, and Boron Trifluoride


Descriptive Note : Master's thesis,


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING


Personal Author(s) : Hauschild, Neal T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a270625.pdf


Report Date : Sep 1993


Pagination or Media Count : 262


Abstract : This study investigated the sensitivity, selectivity, and reversibility of a chemically-sensitive field-effect transistor (CHEMFET) gas microsensor. Various physical operating parameters were tested to determine which produced the most significant sensitivity, selectivity, and reversibility which were computed from response changes generated from electrical conductivity modulations when exposed to challenge gases. The variable operating parameters included: thinfilm material, film thickness, challenge gas specie, challenge gas concentration, and operating temperature. Copper phthalocyanine and lead phthalocyanine were used as thin films to detect the following challenge gases: nitrogen dioxide, dimethyl methylphosphonate, boron trifluoride, methanol, carbon monoxide, vinyl chloride, and trichloroethylene. Tests revealed that copper phthalocyanine was the most sensitive to dimethyl methylphosphonate and boron trifluoride, whereas lead phthalocyanine was the most sensitive to the remaining challenge gases. The CHEMFET was selective to the binary challenge gas combinations. The films were most selective for nitrogen dioxide. The CHEMFET was fully reversibly, and the time duration for full reversibility increased with increasing challenge gas concentrations and increasing time of exposure.


Descriptors :   *THIN FILMS , *SENSITIVITY , *GAS DETECTORS , TEST AND EVALUATION , TEMPERATURE , THICKNESS , FILMS , ELECTRICAL CONDUCTIVITY , TIME , RESPONSE , TRICHLOROETHYLENE , TRANSISTORS , BORON , MODULATION , CARBON MONOXIDE , CHLORIDES , PHTHALOCYANINES , METHANOLS , COPPER , NITROGEN DIOXIDE , MONOXIDES , DIOXIDES , VARIABLES , NITROGEN , CARBON , FIELD EFFECT TRANSISTORS , CONDUCTIVITY , PARAMETERS , MATERIALS


Subject Categories : Electrical and Electronic Equipment
      Miscellaneous Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE