Molecular Electronics

Published on Dec 17, 2015


Will silicon technology become obsolete in future like the value technology done about 50 years ago? Scientists and technologists working in anew field of electronics, known as molecular electronics is a relatively new field, which emerged as an important area of research only in the 1980's. It was through the efforts of late professor Carter of the U.S.A that the field was born.

Conventional electronics technology is much indebted to the integrated circuit (IC) technology. IC technology is one of the important aspects that brought about a revolution in electronics. With the gradual increased scale of integration, electronics age has passed through SSI (small scale integration), MSI (medium scale integration), LSI (large scale integration), and ULSI (ultra large scale integration). These may be respectively classified as integration technology with 1-12 gates, 12-30 gates, 30-300 gates, 300-10000 gates, and beyond 10000 gates on a single chip.

The density of IC technology is increasing in pace with Famous Moore's law of 1965. Till date Moore's law about the doubling of the number of components in an I.C every year holds good. He wrote in his original paper entitled 'Cramming More Components Onto Integrated Circuit ', that, "the complexity for minimum component costs has increased at the rate of roughly a factor of 2 per year. Certainly, over the short term, this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe that it will not remain constant for at least ten more years.

It is now over 30 years since Moore talked of this so called technology-mantra. It is found that I.C's are following his law and there is a prediction that Moore's law shall remain valid till 2010.the prediction was based on a survey of industries and is believed to be correct with research of properties of semiconductors and production processes. But beyond ULSI, a new technology may become competitive to semiconductor technology.

This new technology is known as Molecular electronics. Semiconductor integration beyond ULSI, through conventional electronic technology is facing problems with fundamental physical limitations like quantum effects etc. Molecular based electronics can overcome the fundamental physical and economic issues limiting Silicon Technology.

For a scaling technology beyond ULSI, prof. Forest Carter put forward a novel idea. In digital electronics, 'YES' and 'NO' states are usually and respectively implemented and/or defined by 'ON' and 'OFF' conditions of a switching transistor. Prof. Carter postulated that instead using a transistor; a molecule (a single molecule or a small aggregate of molecule) might be used to represent the two states, namely YES & NO of digital electronics.

For e.g. one can use positive spin & negative spin of a molecule to represent respectively 'YES' & 'NO' states of binary logic. As in the new concept a molecule rather than a transistor is proposed to be used, the scaling technology may go to molecular scale.

It is therefore defined as MSE (molecular scale electronics). MSE is far beyond the ULSI technology in terms of scaling. In order to augment his postulation Prof. Carter conducted a number of international conferences on the subject. The outcome of these conferences has been to establish the field of molecular electronics.