Observation of single hole transport in a highly tunable silicon quantum dot

We report the cryogenic-temperature electrical measurements of a planar silicon metal-oxide-semiconductor (MOS) based single hole transistor. A multi-layer gate electrode architecture allows independent control of hole densities in the leads and quantum dot. Stable Coulomb blockade oscillations are observed over a large range with minimal hysteresis. Separate tunability of the tunneling barrier enables the dot occupancy to reach the last few holes, as demonstrated by source-drain bias spectroscopy. The structure is highly flexible that a double quantum dot can be define by appropriate gate bias.