# Charge detection in gate-defined bilayer graphene quantum dots

## TL;DR

This paper demonstrates charge detection in bilayer graphene quantum dots using an integrated, high-quality charge detector without etching, capable of sensing individual electron charging events and coupled quantum dot states.

## Contribution

It introduces a novel, etching-free fabrication method for bilayer graphene quantum dots with integrated charge detection, enabling sensitive measurement of single-electron charging.

## Key findings

- Charge detector detects single-electron charging events.
- Potential change causes up to 77% current step in detector.
- Detection of charging states in coupled quantum dots.

## Abstract

We report on charge detection in electrostatically-defined quantum dot devices in bilayer graphene using an integrated charge detector. The device is fabricated without any etching and features a graphite back gate, leading to high quality quantum dots. The charge detector is based on a second quantum dot separated from the first dot by depletion underneath a 150 nm wide gate. We show that Coulomb resonances in the sensing dot are sensitive to individual charging events on the nearby quantum dot. The potential change due to single electron charging causes a step-like change (up to 77 %) in the current through the charge detector. Furthermore, the charging states of a quantum dot with tunable tunneling barriers and of coupled quantum dots can be detected.