Single-ZnO-Nanobelt-Based Single-Electron Transistors

We fabricate single electron transistors based on a single ZnO nanobelt using standard micro-fabrication techniques. The transport properties of the devices are characterized at room temperature and at low temperature (4.2 K). At room temperature, the source-drain current increases linearly as the bias voltage increases, indicating a good ohmic contact in the transistors. At 4.2 K, a Coulomb blockade regime is observed up to a bias voltage of a few millivolts. With scanning the back gate voltage, Coulomb oscillations can be clearly resolved with a period around 1 V. From the oscillations, the charging energy for the single electron transistor is calculated to be about 10 meV, which suggests that confined quantum dots exist with sizes around 35 nm in diameter. The irregular Coulomb diamonds are observed due to the multi-tunneling junctions between dots in the nanobelt.