Ambipolar charge sensing of few-charge quantum dots

We demonstrate few-charge occupation of electron and hole quantum dots in silicon via charge sensing. We have fabricated quantum dot (QD) devices in a silicon metal-oxide-semiconductor heterostructure comprising a single-electron transistor next to a single-hole transistor. Both QDs can be tuned to simultaneously sense charge transitions of the other one. We further detect the few-electron and few-hole regimes in the QDs of our device by active charge sensing.