Organic Molecules Challenge :: essays research papers

Organic Molecules Challenge Silicon's Reign as King of Semiconductors There is a revolution fomenting in the semiconductor industry. It may take 30 years or more to reach perfection, but when it does the advance may be so great that today's computers will be little more than calculators compared to what will come after. The revolution is called molecular electronics, and its goal is to depose silicon as king of the computer chip and put carbon in its place. The perpetrators are a few clever chemists trying to use pigment, proteins, polymers, and other organic molecules to carry out the same task that microscopic patterns of silicon and metal do now. For years these researchers worked in secret, mainly at their blackboards, plotting and planning. Now they are beginning to conduct small forays in the laboratory, and their few successes to date lead them to believe they were on the right track. "We have a long way to go before carbon-based electronics replace silicon-based electronics, but we can see now that we hope to revolutionize computer design and performance," said Robert R. Birge, a professor of chemistry, Carnegie- Mellon University, Pittsburgh. "Now it's only a matter of time, hard work, and some luck before molecular electronics start having a noticeable impact." Molecular electronics is so named because it uses molecules to act as the "wires" and "switches" of computer chips. Wires, may someday be replaced by polymers that conduct electricity, such as polyacetylene and polyphenylenesulfide. Another candidate might be organometallic compounds such as porphyrins and phthalocyanines which also conduct electricity. When crystallized, these flat molecules stack like pancakes, and metal ions in their centers line up with one another to form a one-dimensional wire. Many organic molecules can exist in two distinct stable states that differ in some measurable property and are interconvertable. These could be switches of molecular electronics. For example, bacteriorhodpsin, a bacterial pigment, exists in two optical states: one state absorbs green light, the other orange. Shinning green light on the green-absorbing state converts it into the orange state and vice versa. Birge and his coworkers have developed high density memory drives using bacteriorhodopsin. Although the idea of using organic molecules may seem far-fetched, it happens every day throughout nature. "Electron transport in photosynthesis one of the most important energy generating systems in nature, is a real-world example of what we're trying to do," said Phil Seiden, manager of molecular science, IBM, Yorkstown Heights, N.Y. Birge, who heads the Center for Molecular Electronics at Carnegie-Mellon, said two factors are driving this developing revolution, more speed and less space. "Semiconductor chip designers are always trying to cram more electronic