  In this work, we demonstrate a silicon nanocrystal Field Effect Transistor
(ncFET). Its operation is similar to that of a Tunnelling Field Effect
Transistor (TFET) with two barriers in series. The tunnelling barriers are
fabricated in very thin silicon dioxyde and the channel in intrinsic
polycrystalline silicon. The absence of doping eliminates the problem of
achieving sharp doping profiles at the junctions, which has proven a challenge
for large-scale integration and in principle allows scaling down the atomic
level. The demonstrated ncFET features a 10$^4$ on/off current ratio at room
temperature, a low 30 pA/$\mu$m leakage current at a 0.5 V bias, an on-state
current on a par with typical all-Si TFETs and bipolar operation with high
symmetry. Quantum dot transport spectroscopy is used to assess the band
structure and energy levels of the silicon island.
