The first physicist to suggest that electrons could also exhibit wave-like behavior was the French nobleman Louis De Broglie. In 1924, De Broglie proposed the principle of wave-particle duality for all components of matter, not just electrons. This principle means that the particles that constitute matter possess a dual nature, appearing either as particles or as waves, depending on the circumstances. For this groundbreaking idea, De Broglie was awarded the Nobel Prize in Physics in 1929.
The wave-particle duality of electrons was experimentally demonstrated by scientists Clinton Davisson and Lester Germer in the United States, as well as by George Paget Thomson in England. In 1937, both Davisson and Thomson received the Nobel Prize for this discovery. George Paget Thomson was the son of Joseph John Thomson, who first identified electrons as particles.
The Davisson and Germer experiment involved firing a beam of electrons at a nickel crystal. Initially, it was expected that the electrons would behave like tiny balls, bouncing off a surface made up of nickel atoms. However, the electrons scattered in various directions, creating a diffraction pattern that demonstrated their wave-like nature.
Thomson conducted a similar experiment, directing a beam of electrons through extremely thin metal foils. The small gaps between the atoms in these foils functioned like the slits in Thomas Young's double-slit experiment. As the electron beam passed through the foil, Thomson observed a diffraction pattern similar to that seen by his American counterparts. This led him to conclude that electrons also behave as waves.