Dispersive readout of reconfigurable ambipolar quantum dots in a silicon-on-insulator nanowire

We report on ambipolar gate-defined quantum dots in silicon on insulator nanowires fabricated using a customized complementary metal-oxide-semiconductor process. The ambipolarity was achieved by extending a gate over an intrinsic silicon channel to both highly doped n-type and p-type terminals. We utilize the ability to supply ambipolar carrier reservoirs to the silicon channel to demonstrate an ability to reconfigurably define, with the same electrodes, double quantum dots with either holes or electrons. We use gate-based reflectometry to sense the inter-dot charge transition (IDT) of both electron and hole double quantum dots, achieving a minimum integration time of 160 (100) μs for electrons (holes). Our results present the opportunity to combine, in a single device, the long coherence times of electron spins with the electrically controllable hole spins in silicon.