Charge detection in phosphorus-doped silicon double quantum dots

The ability to control and detect single electrons is paramount for the implementation of a scalable charge-based quantum computer and single-electron memory devices. Here, we report charge detection in degenerately phosphorus-doped silicon double quantum dots (DQD) that are electrically connected to an electron reservoir. The sensing device is a single-electron transistor patterned in close proximity to the DQD. We observe steplike behavior and shifts of the Coulomb blockade oscillations in the detector's current as the reservoir's potential is swept. By means of a classical capacitance model, we demonstrate that these features can be used to detect changes in the DQD charge occupancy. © 2010 American Institute of Physics.