title: Charge transfer from ammonia physisorbed on nanotubes.
abstract: We report the use of nanotube field-effect transistor devices for chemical sensing in a conducting liquid environment. Detection of ammonia occurs through the shift of the gate voltage dependence of the source-drain current. We attribute this shift to charge transfer from adsorbed ammonia molecules, with the amount of charge estimated to be as small as 40 electrons for the smallest shift detected. Using the concentration dependence of the response as an adsorption isotherm, we are able to measure the amount of charge transfer to be 0.04 electron per ammonia molecule.
authors.affiliation: Nanomix Inc, Emeryville, California 94608, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Bradley
authors.forename: Jean-Christophe P
authors.initials: JC
authors.lastname: Gabriel
authors.forename: Mikhail
authors.initials: M
authors.lastname: Briman
authors.forename: Alexander
authors.initials: A
authors.lastname: Star
authors.forename: George
authors.initials: G
authors.lastname: Grüner