Molecular Electronics
A family of new technologies that is soon going to turn the computer and consumer electronics industries upside down. Franco Vitaliano

Buckminsterfullerene (C60) - Functions as a molecular-scale AND logic gate

You may be asking "What is Molecular Electronics?

Well, from my current understanding, molecular electronics seeks to use individual molecules to perform functions in electronic circuitry now performed by semiconductor-based solid-state microelectronics (which is the hardware for the brain of the computer). Individual Molecules are being studied to perform functions such as switches, wires and memory elements. These functions have been accomplished by individual molecules in the lab. However, bringing together the billions of functions that are currently being performed on a semiconductor over to the moleuclar level is where the challenge begins.

Individual molecules are hundreds of times smaller than the smallest features conceivably attainable by semiconductor technology. Some research done by companies such as CALMEC suggest that this new technology has vast implications on the electronic future. They have performed research on this new technology which has brought up some probable results:

  • STABILITY- Two equal but opposite energy states in these molecules affords stability while assuring complete reversibility.
  • SPEED- Electrical field switching will potentially provide femptosecond computational switching times. Optical switching will potentially provide nanosecond computational switching times.
  • NANO-ASSEMBLY - The molecules will lend themselves to the new techniques of nano technology self-assembly enabling the assembly of supra-molecular device architectures.
  • NON-DESTRUCTIVE READOUTS - The molecule can be interrogated without energy absorption by means of optical rotation or by measurement of the capacitance at the molecule produced by the dipole.

Why study molecular electronics?
There are many reasons for delving into this new technology. A few of the potential possibilites are blinding processing speed, incredible amounts of storage, very low manufacturing costs, and energy conservation. Also, if what they say is true, this technology will allow us to further push the limits of the mind and allow us to evolve into a new world where biology and technology will eventually be one. The present technology, semiconductor-based solid-state microelectronics, will not allow us to go where our new found knowledge is taking us. One immediate example that molecular electronics will allow is that of a better chance to pursue artifical intelligence.

What are some advantages and disadvantages of molecular computing?

Well, for one, the costs of producing the chips will be much less (when the design process is intact - maybe 50-60 years). Until then the cost of producing these molecular size chips will be in the arena of 50 billion dollars. The second of Moore's laws offers a general layout of the time and cost of producing these chips. The economic situation is that at the time when semiconductor chip fabrication has reached its peak (when the chips are the fastest and cheapest to produce) the economic cost will rise as scientfic cost will decrease (going from the best semiconductor chip to the first molecular chip).

One problem with current silcon based chips is that of the decreasing size. When something is small enough to the point where you are dealing with individual atoms, quantum effects take over. In quantum theory, the Heisenberg uncertainty principal states that just the act of observing such atomic snippets effectively alters the behavior of that which you are observing (i.e., to see it is to change it.) As a consequence, it is impossible to ever know what is precisely going on in the atomic realm. As Franco Vitaliano states "One possible way to overcome quantum effects is to create redundant circuits. By using their summed signals, it may ensure that you are getting predictable behavior out of the Lilliputian circuits, uncertainty principal or no. But as transistor-based systems are not naturally redundant, this feature has to be fabricated in, which adds extra costs to an already expensive proposition. By taking advantage of this natural redundancy, and using averaged output, the molecular systems designer can reasonably predict that the data is being handled correctly, despite quantum effects. This particular technique has been termed ensemble averaging

One problem which molecular electronics may overcome is that of heat loss due to silicon based ciructs; these integrated circuts which work only in one direction (I.E. an AND gate) and are thus irreversible in their operation result in a consequence of the second law of thermodynamics, which in one form states that irreversible process create entropy (or heat). So, whenever an AND gate clears (destroys) one bit of data, it also generates heat. As you build ever faster and denser silicon-based processors that are irreversible in operation, heat dissipation eventually becomes a huge obstacle. In nature, biological systems rely on reversible chemical reactions. Thus, biomolecular materials might be a medium for resolving this issue.

Electrical Engineering is such a broad field that it is hard to choose a path in which to pursue. I belive that molecular electronics will have a profound effect on the future of both computing and living. I think that Kevin Kelly sums it up when he states in his book "Out of Control" that "as we improve our machines they will become more organic, more biological, more like life, because life is the best technology for living. Someday the difference between machines and biology will be hard to discern. Yet "pure" life will still have its place."







Links relating to Molecular Electronics



"Radical departures from present computing design will probably be needed to exploit molecular computing systems fully." Scientific American, June, 2000.


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Note to editor
  1. fullerenes - mimic natural photosynthetic energy and electron transfer.
  2. photovoltaic cells