  We demonstrate that by means of a local top-gate current oscillations can be
observed in extended, monolayered films assembled from monodisperse metal
nanocrystals -- realizing transistor function. The oscillations in this
metal-based system are due to the occurrence of a Coulomb energy gap in the
nanocrystals which is tunable via the nanocrystal size. The nanocrystal
assembly by the Langmuir-Blodgett method yields homogeneous monolayered films
over vast areas. The dielectric oxide layer protects the metal nanocrystal
field-effect transistors from oxidation and leads to stable function for
months. The transistor function can be reached due to the high monodispersity
of the nanocrystals and the high super-crystallinity of the assembled films.
Due to the fact that the film consists of only one monolayer of nanocrystals
and all nanocrystals are simultaneously in the state of Coulomb blockade the
energy levels can be influenced efficiently (limited screening).
