STM/AFM nano-oxidation process to room-temperature-operated single-electron transistor and other devices

Application of a scanning tunneling microscopy (STM) and an atomic force microscopy (AFM) to electron devices and an optical device are introduced in this paper. Using STM tip/AFM cantilever as a cathode, surfaces of a metal or a semiconductor are oxidized to form a few tens of nanometers-wide oxidized metal line or an oxidized semiconductor line, which works as an energy barrier for an electron. A single-electron transistor (SET), a photoconductive switch, and a high-electron mobility transistor (HEMT) are fabricated using this fabrication process. The fabricated SET operates even at high room temperatures and shows the large Coulomb gap and staircase of 200-mV periods and the large Coulomb oscillation periods of 406 mV. The fabricated photoconductive switch shows a ultra-fast response time, i.e., a full-width at half-maximum response of 380 fs at a bias voltage of 10 V. The drain current of HEMT was controlled by the oxidized semiconductor wire on the channel region formed by this fabrication process.