Methods to manufacture metal nanopins and metal oxide nanopins are disclosed. Metal nanopins are fabricated on a metal foil by capillaritron plasma source dry etching. The aspect ratio and the density of metal nanopins are controlled by adjusting the temperature of the metal foil during ion beam dry etching. The end radius of metal nanopins less than 10 nm and the aspect ratio of metal nanopins between 25 and 30 can be achieved. Besides, metal oxide nanopins are fabricated by ion implantation and thermal oxidation. The metal foil is implanted with ions and then thermally oxidized to form the metal oxide nanopins. It shows that the metal oxide nanopins fabricated with oxygen implantation exhibit better field emission properties.