title: Sumio Iijima
context: Sumio Iijima (飯島 澄男 Iijima Sumio, born May 2, 1939) is a Japanese physicist, often cited as the inventor of carbon nanotubes.  Although carbon nanotubes had been observed prior to his "invention", Iijima's 1991 paper generated unprecedented interest in the carbon nanostructures and has since fueled intense research in the area of nanotechnology.
question: Who invented the carbon nanotube?
answers: Sumio Iijima