Zhores Alferov, whose independent development of semiconductor laser structures earned him a Nobel prize in physics, has died at the age of 88.
Recognized by the Nobel committee in 2000, Alferov shared that year’s award with fellow laser developer Herbert Kroemer and integrated circuit pioneer Jack Kilby, for work that collectively helped usher in a revolution in information technology and modern communications.
Alferov’s key contribution involved producing the advanced semiconductor heterostructures – ultrathin layers of slightly different compounds – that were, unlike silicon, able to emit light.
The high-speed lasers and optoelectronic devices that resulted from his and Kroemer’s efforts have ended up underpinning optical communications and the internet.
Double heterostructures
Born in Vitebsk, Russia, in 1930, Alferov studied physics at the V. I. Ulyanov (Lenin) Electrotechnical Institute in Leningrad (now St. Petersburg), before joining the hugely influential Ioffe Physical-Technical Institute.
After earning his doctorate in 1970, Alferov spent the rest of his career at Ioffe, and in 1987 became the institute’s director. He would also lead the Leningrad-St. Petersburg branch of the Russian Academy of Sciences, and aside from the Nobel won numerous other awards.
In the early 1960s, Alferov filed a patent application describing the principle of the double-heterostructure (DHS) laser diode. The approach confines photons to an active region of the layered semiconductor structure, while acting like an optical waveguide, to generate laser emission.
Critically, Alferov’s group at Ioffe was able to both reduce the threshold current of such devices and enable continuous-wave (CW) operation without the need for cooling – helping make the lasers practical devices suited to commercial deployment. The team published details of a pulsed laser in 1968, and a CW device operating at room temperature in 1970.
Coming at the height of Cold War tensions, and with no direct interaction between US and Russian researchers, groups at Bell Laboratories, RCA, and IBM developed similar devices independently.
“Of utmost importance was, beyond doubt, making low-threshold, room-temperature operating lasers on a DHS that had been suggested by us as far back as 1963,” recalled Alferov in his Nobel biography.
“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.
“In 1968-1969, we virtually realized all the ideas on control of the electron and light fluxes in classical heterostructures based on the arsenide-gallium-arsenide aluminum system.”
The importance of science
Alferov also wrote that achieving the first room-temperature, CW operation of the laser diode structure was, in his opinion, a rare example of open and friendly competition between laboratories belonging to the “antagonistic great powers” of the time.
“We won the competition overtaking by a month Panish’s group in Bell Telephone,” Alferov added. “[The] significance of obtaining the CW regime had the 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 [the] appearance and rapid development of optical fiber communication.”
Shortly after that key breakthrough, Alferov was able to spend six months working with fellow optoelectronics pioneer Nick Holonyak - inventor of the first visible-range LED and laser diode - at the University of Illinois.
Reflecting more widely on the importance of scientific research in his Nobel biography, Alferov wrote:
“All that had been made by human beings, in principle, was made due to science. And if our country’s choice is to be a Great Power, Russia will be the great power not because of the nuclear potential, not because of faith in God or president, or western investments but thanks to the labor of the nation, faith in knowledge and science, and thanks to the maintenance and development of scientific potential and education.”
Alferov, who in 2015 gave a presentation during the launch ceremony for the International Year of Light at UNESCO headquarters in Paris, died March 1. He is survived by his wife and three children.
