Temperature and Magnetic Field Studies of AFM Patterned Nanoscale Devices

Nanoscale electronic devices based on the single electron transistor (SET) were patterned using atomic force microscope (AFM) nanolithography by selective oxidation. Material systems based on Ti, Ni, Fe, Al, AlGaAs and SiGe were used. The devices, with minimum feature sizes of 20-50 nm, were tested from 4-300K and from 1-10T. The devices exhibited Coulomb blockade effects at room temperature with step widths of several hundred millivolts. Magnetic field measurements altered the coulomb blockade mechanism through enhanced negative magnetoresistance or through excitation of the Landau levels.