Single-electron pumping in a ZnO single-nanobelt quantum dot transistor

Abstract

Diluted magnetic semiconductors (DMSs) have traditionally been employed to implement spin-based quantum computing and quantum information processing. However, their low Curie temperature is a major hurdle in their use in this field, which creates the necessity for wide bandgap DMSs operating at room temperature. In view of this, a single-electron transistor (SET) with a global back-gate was built using a wide bandgap ZnO nanobelt (NB). Clear Coulomb oscillations were observed at 4.2 K. The periodicity of the Coulomb diamonds indicates that the Coulomb oscillations arise from single quantum dots of uniform size, whereas quasi-periodic Coulomb diamonds correspond to the contribution of multi-dots present in the ZnO NB. By applying an AC signal to the global back-gate across a Coulomb peak with varying frequencies, single-electron pumping was observed; the increase in current was equal to the production of electron charge and frequency. The current accuracy of about 1% for both single- and double-electron pumping was achieved at a high frequency of 25 MHz. This accurate single-electron pumping makes the ZnO NB SET suitable for single-spin injection and detection, which has great potential for applications in quantum information technology.