Igor Grekhov

Igor Vsevolodovich Grekhov was born on 10 September 1934 in Smolensk, in western Russia, into a family of schoolteachers. His childhood was spent in Simferopol in Crimea, where he finished secondary school with a gold medal.

He went on to the Bauman Moscow Higher Technical School, one of the leading engineering universities in the Soviet Union, and graduated in 1958 as a mechanical engineer. Under the Soviet system of job assignment he was sent to the Elektrovypryamitel factory in Saransk, in the Mordovian ASSR, where from 1958 to 1962 he worked as an engineer and then as head of the semiconductor laboratory.

In 1962 Grekhov moved to Leningrad and joined the Physical Technical Institute of the USSR Academy of Sciences, later the Ioffe Institute. He stayed there for the rest of his working life, rising from junior researcher to senior researcher, sector head, head of the laboratory of power semiconductor devices, head of department and director of a division. In his final years he was chief researcher of the laboratory.

He defended his candidate dissertation in 1967 under academician Vladimir Tuchkevich, and his doctoral dissertation in 1974, both in the physics of semiconductors. Between 1960 and 1975 he was one of the leading members of Tuchkevich's team, which created high-power semiconductor device engineering as a new branch of Soviet industry. He headed the power electronics laboratory from 1982 to 2019 and the institute's solid-state electronics department from 2004 to 2014.

His research into electron-hole plasma in semiconductors made it possible to raise the pulsed power of devices by orders of magnitude. The devices developed under his leadership included the reversely switched dynistor, able to switch currents in the megaampere range, the drift step recovery diode, subnanosecond pulse sharpeners and the integrated thyristor with field-effect control. They found use in power supplies for lasers and accelerators and in many industrial pulse technologies. He also helped found Megaimpuls, a company that makes generators based on these devices.

In 1975 he presented a review of Soviet power electronics at the IEDM conference in Washington. He taught a course on the physics of semiconductor devices at the Leningrad Polytechnic Institute in the 1980s and 1990s, supervised more than 30 candidates of science, and sat on the editorial board of the journal Technical Physics Letters. He was elected a corresponding member of the USSR Academy of Sciences in 1991 and a full member of the Russian Academy of Sciences in 2008.

Grekhov was married, and his wife worked at the Russian Museum in St Petersburg. They had a son.

For almost forty years, from 1962 to 2000, he was a dedicated mountaineer. He became a candidate master of sport in 1976 and made more than 150 ascents, including 23 of the fifth difficulty category, three first ascents and two climbs of peaks above 7,000 metres. He also worked as a climbing instructor and took part in mountain rescue operations.

Igor Grekhov died on 30 August 2026 in St Petersburg, aged 91. The Ioffe Institute announced his death with deep sorrow, describing him as an outstanding scientist and a brilliant specialist in high-power semiconductor electronics and pulse technology, and listing his Lenin Prize, two State Prizes and Government Prize, and his Orders of Honour, Friendship and Friendship of Peoples. The cause of his death has not been made public.

Grekhov is remembered as one of the people who built Soviet power semiconductor engineering from its beginnings, and as the inventor of pulsed switching devices that are still used in high-power physics and industry. He co-wrote four books, more than 600 scientific papers and about 200 inventions, and ten of his students went on to earn doctorates of their own. The laboratory he led for nearly four decades at the Ioffe Institute continues his work on silicon and silicon carbide power devices.