10-04-2017, 08:31 PM
[attachment=5706]
Nanocell Logic Gates For Molecular Computing
Molecular electronics seeks to build computational systems, both memory and
logic, wherein individual or small collections of molecules serve as discrete device
components. Potential advantages of molecular electronic systems could be many-fold
including reducing the complexity and cost of current integrated circuit fabrication
technologies, reducing heat generation by using only a few electrons per bit of
information, and providing a route to meet the ever-continuing demand for
miniaturization. While molecules are approximately one million times smaller in area than
their present-day solid state counterparts, this small size brings with it a new set of
problems. In order to take advantage of the ultrasmall size of molecules, one ideally needs
an interconnect technology that: 1) scales from the molecular dimensions; 2) can be
structured to permit the formation of the molecular equivalent of large-scale diverse
modular logic blocks as found in very large-scale interconnect (VLSI) architectures; and
3) can be selectively connected to mesoscopically (100 nm scale) defined input output (I/
O). Three architectures that have previously been described are the teramac, nanofabric,
and the quantum dot cellular automata (QCA). Although these routes possess some
distinct advantages, they are dependent upon precise molecular order and on building
arrays of logic via exact arrays of nanostructures. Moreover, the I/O challenges remain
enormous in those architectural models. The nanocell approach described here is not
dependent on placing molecules in precise orientations or locations and the lithographic
challenges of the I/O structure become trivial, however, programming issues become far
more challenging.