Silicon nanoISFET in Nanoletters

New article on silicon nanowire nanoISFET

The new article with title “Al₂O₃/Silicon NanoISFET with Near Ideal Nernstian Response” has recently been published on Nano Letters. Silicon nanoISFETs with near atomically perfect interfaces have been presented as ultrasensitive pH sensors. Three variations of a SiO₂ gate-oxide and an ALD Al₂O₃ gate-oxide have been deposited on the nanoISFETs and titration experiments were used to assess the pH behavior and sensitivity.

Titration measurements of the nanoISFETs with SiO₂ surfaces reveal the well-known non-linear behavior for pH in the range from 2 to 5, a pH sensitivity of 51.23.7 mV/pH in the pH range from 8 to 10. Surface modifications to the SiO₂ surface with APTES and HMDS monolayers demonstrate the ability to control the pH response by altering the surface charge density with the functional end groups of the monolayer. The measured pH response of the nanoISFETs with thin ALD layers has resulted in nearly perfect Nernstian responses of pH 57.8 1.2 mV/pH at 22 C and in measurement temperature of 0.19 mV/pH C. The extracted ∆pK 1.5 from fitting the measured responses to the Site-Binding Model (SBM) further support the high pH sensitivity measurements. The NanoISFET sensors provide a useful platform for pH sensing due to their simple design and fabrication with high sensitivity and reproducibility.

The paper can be found in Nano Letters: 10.1021/nl200623n

For more information, please contact Songyue Chen: s.chen@utwente.nl