  Field effect transistors with channels made of graphene layer(s) were
explored. The graphene layer(s) contacted a distributed array of well-separated
semiconductor quantum dots (QDs). The dots were embedded in nano-structured
hole-array; each filled hole was occupied by one dot. Differential optical and
electrical conductance was observed. Since Negative Differential Resistance
(NDR) is key to high-speed elements, such construction may open the door for
new electro-photonic devices.
