|NOBEL PRIZE WINNERS|
October 10, 2000
MARGARET WARNER: The six scientists who shared the Nobel Prizes is physics and chemistry today were honored for work that has practical application in consumers' everyday lives. Professor Herbert Kroemer, the University of California at Santa Barbara, was one of three men sharing the physics prize for improving the information technology that makes calculators, CD players and cell phones possible. Professor Allen MacDiarmid of the University of Pennsylvania was one of three men sharing the chemistry prize for discovering that plastic can be made to conduct electricity. The discovery has generated major new developments in a range of products, including film, televisions and computer screens.
Welcome to you both. And congratulations. Professor Kroemer, how did you hear the news, and what was your first reaction?
HERBERT KROEMER: Well, the news came as a telephone call at 2:30 in the morning, and the first reaction is, who on earth is calling at this God-awful hour. But then it became very clear that it was a call from Stockholm. And I think we all know what a call from Stockholm means on this particular day because of course we knew that this was the day for the physics Nobel Prize. So it was very exciting.
MARGARET WARNER: Professor MacDiarmid, it wasn't quite as early in the morning for you on the East Coast.
ALLEN MacDIARMID: That's very true.
MARGARET WARNER: How did you react? Were you surprised?
ALLEN MacDIARMID: Well, I heard over radio that the Physics Prize had been awarded and that the chemistry prize would be announced later, and at about 9:30, I had a phone call from a colleague at the University of Utah. And he started saying congratulations. And I said, "is this a hoax?". And he said, "I got it from the Web." And I said, "well, the Web also has hoaxes at times." But then I started to get some phone calls from reporters in Germany and France and elsewhere. So I thought probably it was correct.
MARGARET WARNER: You knew it was for real. Okay. Professor Kroemer, try, if you could, or please in layman's terms, explain your discovery, and... well, explain your discovery for which you were honored.
ALLEN MacDIARMID: Well, it was for work in the field of what we call heterostructures. Heterostructures are semiconductor structures, and of course semiconductors are the foundation of today's electronic devices. And I had the idea back in 1957 first that one could build greatly improved devices by combining more than one, two or even more, into a common device structure in such a way that the transition from one material to the other was a transition with a very high degree of structural perfection and that in this particular case, the interface itself became in effect the active region of the device because there were new forces at that interface acting on the electrons in the semiconductor, which of course make the semiconductor work.
MARGARET WARNER: And just... sorry. Could I just... explain, when you say semiconductors, you're talking about materials like silicon that do generate electricity, that do conduct electricity?
ALLEN MacDIARMID: Yes, semiconductors are materials with a much lower conductivity than metals. That is an important part; the conductivity can be controlled by external means. And that makes devices possible that draw on this control mechanism to generate amplifiers, computer chips, and light-emitting devices like lasers.
MARGARET WARNER: So what have been the practical uses for combining these, as you discovered could be done into these heterostructures?
ALLEN MacDIARMID: Yes. First of all, already existing classes of devices acquire much better performance, for example. They operate faster. And that was in my initial motivation in this work. But then I very quickly realized that this would also make devices possible that simply could not be built without heterostructures, and the dominant example of that one is the semiconductor laser diode, which has become very, very important. It plays a role in many devices. And even those who have never seen laser diodes probably have seen ordinary light-emitting diodes, which also utilize this principle.
MARGARET WARNER: And you're talking about even the little window on your cell phone or things like that?
ALLEN MacDIARMID: No, not the window on the cell phone. That uses a different kind of technology. But in the cell phone, there typically are some particular kind of transistors that draw on this heterostructure technology in order to give them the kind of performance that is necessary for the cell phone technology. Basically very, very sensitive receivers
MARGARET WARNER: I see.
ALLEN MacDIARMID: that make it possible to pick up very weak signals.
MARGARET WARNER: Okay. Professor MacDiarmid, give us an explanation of your discovery.
ALLEN MacDIARMID: Well, our work was a highly type of research involving ourselves, that is Shirakawa and myself in chemistry and my colleague Alan Heeger in physics. And this involved the conversion for the first time of a plastic, which is composed of polymers, from an insulator to a metal. Normally, of course, we always have considered plastic to be insulators. They are wrapped around electrical wiring to stop electricity shorting out. And we found that very readily by doping some certain types of polymers, we could convert the polymer from an insulator to a metal, but a metal which had the physical properties still of a conventional plastic, where you could bend it. It could be processed. But it had the electrical and magnetic properties of a conventional metal. And therefore it has been - come to be known as a synthetic metal or as a conductive polymer.
MARGARET WARNER: Can you explain... what was the secret to getting these polymers able to conduct electricity?
ALLEN MacDIARMID: Very good question. In a regular polymer, the electrons are bound very, very tightly to the polymer backbone so that when you apply an electric voltage potential between two parts of a polymer, the electrons have very great difficulty in moving from one electrode to the other. And therefore the polymer is said to be an electrical insulator. However, when you so called dope it, for example, treat the polymer with a very small amount of something such as iodine, say a tincture of iodine, which we all tend to have in our medicine cabinets in the bathroom, the iodine then pulls some of the electrons out of the polymer, and the remaining electrons then have much greater freedom of movement. For example, if you have a million people say packed into a city square, then it's very difficult for one person to move from one side of the square to the other. However, if you remove a whole lot of people from the square, then a person can then very much more easily move from one side to the other.
MARGARET WARNER: Now, you said you pointed out that these polymer, these plastic, of course, are much more flexible and lighter. Give us a couple of ideas of products this may lead to that we don't have today -- or that are in their infancy today.
ALLEN MacDIARMID: Right. For quite a long time, we have had patents and papers describing the use of these poll masters doing polymers for storing electricity in novel types of rechargeable plastic batteries. The most exciting use at the moment involves the polymers in forming light-emitting diodes very inexpensively and a light-emitting diodes, as was mentioned in the previous discussion a few minutes ago, involves applying a few volts, say between three and ten volts, across a piece of plastic in our case, and the plastic will then emit light and light of various colors depending on what plastic one uses. These are now in production for use in particularly automobiles for dashboards so you can have the various components of the dashboard lighted up and also they will be appearing very shortly in cellular phones. And as we all know, it's difficult to see cellular phones when you're in the car at night, whereas if you had something that was all lit up, that would be very, very much more helpful.
MARGARET WARNER: Professor Kroemer, let me get back to you. I'm struck by the fact that one of you won in physics and one chemistry. You're both dealing with electricity, you're both dealing with diodes. I mean, does this tell me something about the way science is evolving -- that these disciplines aren't maybe as different as they were?
HERBERT KROEMER: There is certainly a great deal of commonality, particularly in the conducting materials field between physics and chemistry. You cannot really separate this one. In my own work, it was more physics dominated than chemistry dominated. But even in my work, in order to build those structures, we had to draw on chemical knowledge but of a very different kind from the chemistry of conducting polymers. It was more the chemistry of crystalline structures similar to silicon and derivatives going beyond silicon, like calcium -
MARGARET WARNER: Let me ask you one final question to you both. What are you going to do with the money? I think it's between $200,000 and $300,000, and is this going to change your life, Professor Kroemer?
HERBERT KROEMER: I will try very hard not to have anything change my life, but I really have not given any thought yet to what I would do with the money. It came as too much of a surprise.
MARGARET WARNER: And, Professor MacDiarmid?
ALLEN MacDIARMID: Several people have asked me that same question today, and I didn't know until a short time ago actually how much was involved. At least one can have more beef stake rather than hamburgers, but my prime concern is to be able to give at least some of that money to help the undergraduates and graduate teaching and research at my University of Pennsylvania.
MARGARET WARNER: Terrific. And again, congratulations to both of you.
ALLEN MacDIARMID: Thank you very much.