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Read an excerpt from Zh.I. Alferov’s autobiography and speak about the most important facts of his scientific career.
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Read an excerpt from Zh. I. Alferov’s autobiography and speak about the most important facts of his scientific career.
Autobiography
I remember my first attendance of the seminar on semiconductors at the Physico-Technical Institute in February 1953 as one of the most impressive events I have ever experienced. That was a brilliant report delivered by E. F. Gross about the discovery of the exciton. The sensation I experienced then could not be compared with anything else. I was stunned by the talk on the birth of a discovery in the area of science to which I myself had got an access.
Yet the main thing was everyday experimental work in the laboratory. Since that time I have been keeping, as a most precious thing, my laboratory daily report book that contains notes of mine about the creation of the first soviet p-n junction transistor on the 5th of March, 1953. And now, when recalling that time I cannot help feeling proud of what we had accomplished. We comprised a team of very young people. Under the guidance of V. M. Tuchkevich we succeeded in working out the principles of technology and metrics of transistor electronics. Below are the names of researchers who had been working in our small laboratory: A. A. Lebedev, a Leningrad University graduate — the growth and doping of perfect germanium single crystals; Zh. I. Alferov — the preparation of transistors, their parameters being at the level of the best world samples; A. I. Uvarov and S. M. Ruvkin - the creation of precise metrics of germanium single crystals and transistors; N. S. Yakovchuk, a graduate of the Faculty of Radio Engineering of Leningrad Electrical Technical Institute — designing transistor-based circuits.
As early as May 1953, the first Soviet transistor receivers were shown to the " top authorities". That work, the performers of which had been working with passion peculiar to their young hearts and with utmost sense of responsibility, exerted a great influence upon me. While quickly and effectively progressing as a scientist, I began to comprehend the significance of the technology not only for electronic devices, but for basic research work too, in regard to notorious " minor" details and sporadic results. And it is since then that I prefer to analyze experimental results proceeding from " simple" general laws prior to putting forward sophisticated explanations.
In subsequent years, our team of researchers at the Physico-Technical institute expanded considerably and in a very short time the first Soviet germanium power rectifiers were created alongside with germanium photodiodes and silicon rectifiers.
In May 1958, Anatolii Petrovic Alexandrov (later the President of the Academy of Sciences of the USSR) asked our team to work out a special semiconductor device for the first Soviet atomic submarine. That required a perfectly new technology and, in addition, another construction of germanium rectifiers, which had been made in a record short space of time. In the month of October, these devices were mounted on a submarine. I was a junior research associate at the Institute then, and was somewhat surprised by a telephone call from the first Vice-Chairman of the Government of the USSR, Dmitrii Fedorovich Ustinov, who asked me of a fortnight reduction of the term. There was no getting away from that: I directly moved to the laboratory premises and settled there but, of course, the request was fulfilled. Later I was decorated with my first State Order which I valued very much.
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In 1961, I defended my candidate thesis that was mainly devoted to working out and investigating power germanium and partially silicon rectifiers. Soviet power semiconductor electronics became possible as a result of those works. Of great importance there, in the sense of a scientific, purely physical standpoint, was a conclusion drawn by me that in p-i-n, p-n-n semiconductor homostructures under working current densities (for most of semiconductor devices) the current was determined by recombination in heavily doped p- and n (n+)-regions while the recombination contribution in the middle i(n)-region of a homostructure was not the determining one: so as soon as the first work on semiconductor lasers appeared, it was natural for me to consider the advantages of employing the double heterostructure of p-i-n (p-n-n+, n-n-p+) type in lasers. The idea was formulated by us shortly after the appearance of the first work of R. Hall with co-workers, which described a semiconductor laser based on a GaAs homo-p-n-structure.
To realize the principal advantages of heterostructures appeared to be possible only after obtaining AlxGal-xAs heterostructures. We did that and it turned out that we had been only one month ahead of American researchers from IBM.
When we began investigating heterostructures, I used to convince my young colleagues, that we were not the only group of scientists in the world who understood the significance of the concept that semiconductor physics and electronics would be developing on the basis of HETERO-, rather than HOMO-structures. Indeed, in 1968 we entered an era of a strong competition with other laboratories in the world, the biggest being American companies: Bell Telephone, IBM and RCA.
In 1967, while on a short trip to the UK, I visited STL laboratories in Harlow. They were well equipped and the experimental base was excellent but English colleagues only discussed theoretical aspects of the heterostructures physics; they did not find experimental study of heterostructures to be promising then.
In 1968–1969, we virtually realized all the ideas of controlling the electron and light fluxes in classical heterostructures based on the arsenide gallium-arsenide aluminum system. Apart from fundamental results that were quite new and important such as efficient one-side injection, the " superinjection" effect, diagonal tunneling, electron and optical confinement in a double heterostructure (which in a short while became the main element in studying the low-dimensional electron gas in semiconductors), we succeeded in employing principal benefits of heterostructure applications in devices, i. e., lasers, LEDs, solar cells, dynistors and transistors. Of utmost importance was, beyond doubts, the making of low threshold room temperature operating lasers on a double heterostructure (DHS) that had been suggested by us as far back as 1963. The approach developed by M. B. Panish and I. Hayashi (Bell Telephone) as well as by H. Kressel (RCA) was different from that of ours since they offered to use a single p-AlGaAs-p-GaAs heterostructure in lasers, which made their approach rather limited. A possibility of obtaining an efficient injection in the heterojunction seemed doubtful to them in spite of the fact that potential advantages of DHS had been recognized.
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In August 1969, I visited the USA for the first time; the paper that I read there at the International Conference on Luminescence in Newark (State of Delaware) was devoted to AlGaAs-based DHS low threshold room temperature lasers and produced an impression of an exploded bomb on American colleagues. Professor Ya. Pankov from RCA, who just shortly before my reading the paper had explained to me that they had not got a permission for me to visit their laboratory, the moment my speech was over told me that the permission had been received. I could not help enjoying my refusal explaining that I had already been invited by that moment to attend IBM and Bell Telephone Laboratories.
My seminar at Bell followed by a visit to the laboratories and discussions with researchers clearly revealed to me merits and demerits of our progress in my laboratory. I believe that worldwide recognition for being the first in getting the continuous wave operation of laser at room temperature was at that time a rare example of an open and friendly competition between laboratories belonging to the antagonistic Great Powers. We won the competition overtaking by a month Panish's group at Bell Telephone. The significance of obtaining the continuous wave regime had a connection first and foremost with working out an optical fiber with low losses as well as the creation of our DHS lasers, which resulted in appearance and rapid development of optical fiber communication.
In winter 1970–1971 and spring 1971, I spent six months in the USA working in the laboratory of semiconductor devices at the University of Illinois together with Prof. Nick Holonyak. We first met in 1967, when he visited my laboratory at the Physico-Technical Institute. Prof. Nick Holonyak, who is one of the founders of semiconductor optoelectronics, the inventor of the first visible semiconductor laser and LED became my closest friend. Now for over 33 years we have been discussing all semiconductor physics and electronics problems, political and life aspects and our interaction (visits, letters, seminars, telephone conversations) has played a very important role in our work and life.
In 1971, I became a recipient of the USA Franklin's Institute gold medal for DHS laser works. Being my first international award, it was of particular value for me. There are Soviet physicists besides me who were given the Franklin's Institute gold medals too: Academician P. L. Kapitsa in 1944; Academician N. N. Bogolubov in 1974; Academician A. D. Sakharov in 1981. I consider it a big honour to belong to such a company!
An AlxGal-xAs system of lattice-matched heterostructures, which in practice seemed to be a lucky exception, was infinitely expanded on the basis of multi-component solid solutions, first theoretically and later on experimentally (InGaAsP is the most convincing example).
Heterostructure-based solar cells were created by us as far back as 1970. And when American scientists published their early works, our solar batteries had already been mounted on the satellites (sputniks) and their industrial production was in full swing. The cells, when being employed in space, proved their efficiency. For many years they had been operating in the " MIR" skylab and in spite of the fact that forecasts of a substantial decrease of the value of one watt of the electrical power have not been justified so far, the most effective energy source in space is, nevertheless, a set of solar cells on heterostructures of III-V compounds.
In 1972, my colleagues and I were awarded the Lenin Prize — the highest scientific Prize in the USSR.
Studies of superlattices and quantum wells were rapidly promoted in the West and afterwards in this country soon resulted in coming into being of a new area of quantum physics of the solid: the physics of low-dimensional electron systems. In this regard, studies of zero-dimensional structures — so-called " quantum dots" — form the summit of the above mentioned works.
(http: /www. /nobelprize. org/nobel_prizes/physics/laureates/2000/alferov-bio. html)
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