Oleg Vladimirovich Losev was a Russian scientist and inventor who made significant discoveries in the field of semiconductor junctions and the light emitting diode.
Although he was never able to complete a formal education and never held a research position, Losev conducted some of the earliest research into semiconductors, publishing 43 papers and receiving 16 "author's certificates" for his discoveries. He observed light emission from carborundum point-contact junctions, constructing a light-emitting diode, did the first research on them, proposed the first correct theory of how they worked, and used them in practical applications such as electroluminescence. He explored negative resistance in semiconductor junctions, and was first to use them practically for amplification, building the first solid-state amplifiers, electronic oscillators, and superheterodyne radio receivers, 25 years before the invention of the transistor. However his achievements were overlooked, and languished unknown for half a century before being recognized in the late 20th and early 21st century.