Of all the honors Kroemer has received over the years, the strangest was the naming of an asteroid after him. (Asteroid Kroemer orbits between Mars and Jupiter.) One honor that he thought beyond the grasp of a physicist who dealt in such a down-to-earth area13 as semiconductors (compared to those who deal with invisible particles) was the Nobel Prize.
"Oh, my name had been mentioned over the years," Kroemer told. But the Nobel Prize is almost invariably awarded for fundamental discoveries, not for applied research, and so I never believed the rumors."
The rumors grew stronger in 1996, when Kroemer was invited to give a talk at a Nobel symposium. "I still didn't catch on," he said. "I looked around at the attendees and saw Horst Stormer, and thought he was the most likely candidate of the group. When he received the prize in 1998, I was enthusiastic and didn't envy him at all - after all, my work was applied." (Stormer and two colleagues received the Nobel Prize for discovering that electrons acting together in strong magnetic fields can form new types of particles with charges thatarefractions of the electronic charge.)
Although Kroemer never believed the Nobel would come to him, he did continue to pay attention to it. On 9 October 2000, the Nobel Prize in Physics was to be announced the next day. He went to bed that evening thinking, "Wouldn't it be funny if I would get a 3 a.m. phone call? But then I said to myself, Stop being silly, go to sleep!" (Noon in Stockholm, when Nobel announcements are typically made, is 3 a.m. in California.)
But when the phone did ring shortly before 3 a.m., his first response was panic - were his children all right? Had something happened to his grandson? His wife answered, and passed him the phone, saying "It's Stockholm."
"If my life depended on it, I could not reconstruct the next two or three sentences," Kroemer says. Then the caller put a friend of Kroemer's on the phone, to reassure him that it was not a joke, warning him that he had about 15 minutes before the public announcement was made and the media circus started.
"At that point all hell did break loose and the phonewasringing off the hook 14, starting with German news agencies, since I'm German and it was already midday there. I literally couldn’t put the phone down."
The Nobel Prize in Physics that year was shared by three people - Jack S. Kilby for his part in developing the IC, and Kroemer and Zhores I. Alferov, for "developing semiconductor heterostructures used in high-speed and opto-electronics." Alferov, working in Russia, had made similar discoveries in parallel with, but separately from, Kroemer; the two first met in 1972 and have since become friends, even though they are, in a sense, competitors.
Kroemer's Nobel citation emphasizes the general principle of the heterostructure, not the individual devices. And that suits him just fine, because he has routinely deferred 15 the question of applications. "Certainly, when I thought of the heterostructure laser, I did not intend to invent compact disc players," he says. "I could not have anticipated the tremendous impact of fiber-optic communications. I really didn't give a damn about what the uses were."
"That's not what I do. The person who comes up with applications thinks differently than the scientist who lays the foundation."