Final Report Summary - SISQ (Silicon Spin Quantum Bits)
We have developed an ambipolar MOSFET-based device that allows the electron and the hole transport regime to be compared in one and the same nanostructure. A top gate overlaps n++ and p++ implanted regions on the source and the drain side. Depending on the applied top gate voltage VL, a two-dimensional electron or hole gas is formed at the Si/SiO2 interface. We locally control the charge density by an additional bottom gate. Non-linear transport measurements show single-charge transport through a QD created underneath the bottom gate. The same charging energy and capacitances of the last charge transition in both regimes indicate that we load the same QD with either an electron or a hole. Ambipolar QDs with single-charge occupancy can break new ground in spin-based QIP, since they have the potential to act as a qubit comparator where the suitability of electron-spin and hole-spin qubits can be evaluated in the same crystalline environment. Taking the advantages of either qubit one could think of future “quantum CMOS” technology based on ambipolar QDs.