Pronunciation: (fēld'ī"un, -ī"on), [key]
a device in which the atomic structure of the surface of a conductor is made visible by introducing helium gas into the device and applying a high voltage to ionize and accelerate the gas toward a fluorescent screen. Cf. field-emission microscope.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.