the invention of the high-electron-mobility transistor (hemt) is usually attributed to physicist takashi mimura (三村 高志), while working at fujitsu in japan. the basis for the hemt was the gaas (gallium arsenide) mosfet (metal-oxide-semiconductor field-effect transistor), which mimura had been researching as an alternative to the standard silicon (si) mosfet since 1977. he conceived the hemt in spring 1979, when he read about a modulated-doped heterojunction superlattice developed at bell labs in the united states, by ray dingle, arthur gossard and horst störmer who filed a patent in april 1978. mimura filed a patent disclosure for a hemt in august 1979, and then a patent later that year. the first demonstration of a hemt device, the d-hemt, was presented by mimura and satoshi hiyamizu in may 1980, and then they later demonstrated the first e-hemt in august 1980.