Nitrate-sensitive field-effect transistor with silica gate insulator modified by chemical grafting
✍ Scribed by V. Rocher; N. Jaffrezic-Renault; H. Perrot; Y. Chevalier; P. Le Perchec
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 434 KB
- Volume
- 256
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
NItrate-sensltlve
Ion-sensltlve field effect transistors (ISFETs) were prepared by chemical graftmg of the slhca gate msulator surface A dlfferentlal measurement mode between a reference ISFET with an Ion-msensltlve surface and an ISFET was used The msensltlve layer was prepared by graftmg 3-chloropropyldunethylchlorosdane on to s~hcon dloxlde and the sensltwe layer by functlonahzmg the grafted chlorosdane with trlmethylamme This sensor showed a hnear response of about 13 mV (pNO$' from 10e3 to 10-l M The pH response was 5 mV (pH)-' from pH 2 to 7 The response for other amons (Cl-, H,PO;, SO:-) was tested, the selectivity ratios compared wth mtrate Ions were 0 6, 0 4 and 0 2, respectwely
The response for mtrate ion was evaluated accordmg to the extended site bmdmg theory apphed to the chemically modified sd~ca/electrolyte Interface Tins allowed the graftmg dens@ to be estimated, and it was found to be 0 25%, the complexatlon constant was found to be lo+' 3