I used simulator such as fettoy and moscnt for device simulation. However, I tried to find a mechanism for utilizing the CNTFET Fettoy as biosensor by relation the permittivity of the Gate Oxide to permittivity of DNA ,but i could not reach any clue. So that, I would like to know the following: 1) Is there a relation between gate oxide permittivity and that of DNA, so that i can simulate the DNA as gate oxide through permittivity? 2) Is there a direct simulator or way for simulating CNTFET as Biosensor with variation in sensitivity, selectivity and setting time?