Oleg Losev

• 1. Introduction

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  Oleg Vladimirovich Losev was born on the 10th of May 1903 in Tver, Russia, into a noble family whose aristocratic background would soon become a liability rather than an advantage. When the Bolshevik Revolution upended Russian society, class origins closed the doors of universities and research institutions to men like Losev. He never completed a college education. He never led a research team. For most of his working life, he held only the title of technician. And yet, working largely alone and without institutional support, he built the first light-emitting diode, the first solid-state amplifier, the first solid-state oscillator, and the first solid-state radio receiver, a full 25 years before the invention of the transistor. He published 43 papers and received 16 inventor's certificates, the Soviet equivalent of patents. His achievements were then overlooked for half a century. How does a scientist of such scope disappear from history? And what exactly did he build in those cramped, under-resourced laboratories?

• 2. A Nobleman in the New Order

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  Losev graduated from secondary school in 1920, just three years after the Bolshevik Revolution had transformed Russia. His father had been a retired captain in the Tsarist Imperial Army and worked at the Tverskoy Vagonostroitelniy Zavod, the local rolling stock factory in Tver. That upper-class background now made higher education impossible for Losev under Soviet policy. Rather than waiting, he went to work as a technician at the Nizhny Novgorod Radio Laboratory, known by its Russian initials NNRL. This was the new Soviet government's first radio science laboratory, recently established in Nizhny Novgorod. He managed to attend a few classes but remained self-taught for the rest of his life. The NNRL proved to be a formative environment despite its constraints. Losev turned his attention to the point-contact crystal detector, sometimes called a cat's whisker detector, which had been used as a demodulator in early crystal radios before powered vacuum tube radios emerged in World War 1. These crude semiconductor diodes were the first semiconductor electronic devices ever built, and almost nothing was scientifically understood about how they functioned. Losev would spend the next two decades trying to answer that question. When the NNRL was shut down in 1928, he transferred with many of its research staff to the Central Radio Laboratory in Leningrad.

• 3. The Green Glow

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  Around 1924, while working as a technician at Nizhny Novgorod and investigating biased crystal junctions, Losev passed direct current through a silicon carbide point contact junction and noticed something no one had properly studied before. A spot of greenish light appeared at the contact point. Losev had constructed a light-emitting diode. The effect had been briefly noted in 1907 by Henry Joseph Round, a British Marconi engineer, who published only a two-paragraph note on it and pursued it no further. Losev was the first to investigate the phenomenon rigorously, the first to propose a theory of how it worked, and the first to envision practical applications. In 1927 he published a detailed account in a Russian journal. The series of articles he went on to publish between 1924 and 1941 amounts to a thorough scientific study of the device. Losev measured rates of evaporation of benzine from the crystal surface during light emission to test whether heat was involved. The evaporation was not accelerated, which led him to conclude the luminescence was a cold light, not caused by thermal effects. He theorized that the correct explanation lay in the then-new science of quantum mechanics, specifically that the effect was the inverse of the photoelectric effect that Albert Einstein had explained in 1905. He wrote to Einstein about this speculation but did not receive a reply. Losev also patented a device he called the Light Relay and foresaw its use in telecommunications. Silicon carbide, the material he used, is an indirect bandgap semiconductor and was far less efficient than the direct bandgap materials such as gallium nitride used in modern LEDs. Only Losev saw potential in those weak green lights.

• 4. Crystodyne and the Solid State

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  Since around 1909, researchers including William Henry Eccles and G. W. Pickard had noticed that applying a DC bias voltage to a cat's whisker detector could occasionally cause the device to break into spontaneous oscillation. This negative resistance effect was observed but largely ignored. In 1923 Losev began investigating what he called oscillating crystals. He discovered that biased zincite, a zinc oxide crystal, could amplify a signal. Losev grasped immediately what this meant. Negative resistance diodes could replace vacuum tubes, offering simpler and cheaper alternatives to the dominant technology of the era. He built solid-state amplifiers, oscillators, tuned radio frequency receivers, regenerative receivers, and even a superheterodyne receiver, operating at frequencies up to 5 MHz. All of this was accomplished 25 years before the transistor. Hugo Gernsback, an influential figure in early electronics, gave the technology the name Crystodyne. Despite that recognition, the Soviet authorities did not provide support. Zincite crystals presented a further problem: they had to be imported from the United States, making steady supply uncertain. After a decade of research, Losev abandoned the work and the technology faded from view. Negative resistance in diodes was independently rediscovered in 1956 with the tunnel diode. Today, negative resistance devices such as the Gunn diode and the IMPATT diode are among the most widely used sources of microwaves.

• 5. Recognition Deferred

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  At the invitation of director Abram Ioffe, Losev conducted research at the Ioffe Physical-Technical Institute from 1929 to 1933. In 1938, the Institute awarded him a PhD without requiring a formal thesis. The recognition came too late to benefit his career. By 1937 he had been forced to accept a position as a technician at the physics department of the Leningrad First Medical Institute, an institution with no connection to his research interests. He stayed there until 1942. Losev died of starvation on the 22nd of January 1942, at the age of 38, during the Siege of Leningrad. He died alongside many other civilians as German forces blockaded the city in World War 2. His place of burial is not known. The scientific community largely passed over his work for decades. In 1951, Kurt Lehovec and colleagues published a paper in Physical Review that cited Losev's work on LEDs, though his name appeared in that paper as Lossew. The fuller reckoning came later still. In the April 2007 issue of Nature Photonics, Nikolay Zheludev published an account crediting Losev with the invention of the LED, bringing his story to a wide scientific audience for the first time in the early 21st century.