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

TL;DR

This paper demonstrates reconfigurable ambipolar quantum dots in silicon-on-insulator nanowires, enabling the same device to host both electron and hole quantum dots for potential quantum computing applications.

Contribution

It introduces a CMOS-compatible fabrication method for ambipolar quantum dots in SOI nanowires, allowing reconfigurable control of electron and hole quantum dots within a single device.

Findings

Successful creation of ambipolar quantum dots in SOI nanowires.

Reconfigurable quantum dots with both electrons and holes.

Fast charge sensing with gate-based reflectometry.

Abstract

We report on ambipolar gate-defined quantum dots in silicon on insulator (SOI) nanowires fabricated using a customised complementary metal-oxide-semiconductor (CMOS) 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 utilise 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) $\mu$s 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 holes spins in silicon.