Modeling electrostatic and quantum detection of molecules

Smitha Vasudevan, Kamil Walczak, Neeti Kapur, Matt Neurock, Avik W. Ghosh

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We describe two different modes for electronically detecting an adsorbed molecule using a nanoscale transistor. The attachment of an ionic molecular target shifts the threshold voltage through modulation of the depletion layer electrostatics. A stronger bonding between the molecule and the channel, involving actual overlap of their quantum mechanical wavefunctions, leads to scattering by the molecular traps that creates characteristic fingerprints when scanned with a backgate. We describe a theoretical approach to model these transport characteristics.

Original languageEnglish (US)
Article number4529224
Pages (from-to)857-862
Number of pages6
JournalIEEE Sensors Journal
Issue number6
StatePublished - Jun 2008

Bibliographical note

Funding Information:
Manuscript received July 31, 2007; revised January 25, 2008 and February 12, 2008. This work was supported in part by DARPA-AFOSR, in part by NSF-NIRT, and in part by the NSF Career Award. The associate editor coordinating the review of this paper and approving it for publication was Prof. Robert Trew.

Copyright 2008 Elsevier B.V., All rights reserved.


  • Coulomb scattering
  • Field-effect transistor (FET)
  • Quantum interference
  • Random telegraph signal (RTS)
  • Time-dependent NEGF


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