# Passivation and characterization of charge defects in ambipolar silicon quantum dots

## TL;DR

This paper investigates charge defects in silicon quantum dots, demonstrating a passivation process using annealing with Al₂O₃ that reduces defects and enables the formation of longer quantum dots, while revealing persistent amphoteric defects.

## Contribution

It introduces a barrier array structure for defect probing and demonstrates defect passivation via annealing, advancing silicon quantum dot fabrication techniques.

## Key findings

- Annealing reduces majority charge defects in silicon quantum dots.
- Longer hole quantum dots up to 180 nm are achieved after passivation.
- Persistent amphoteric charge defects remain post-annealing with ~10 meV charging energy.

## Abstract

In this Report we show the role of charge defects in the context of the formation of electrostatically defined quantum dots. We introduce a barrier array structure to probe defects at multiple locations in a single device. We measure samples both before and after an annealing process which uses an Al$_2$O$_3$ overlayer, grown by atomic layer deposition. After passivation of the majority of charge defects with annealing we can electrostatically define hole quantum dots up to 180 nm in length. Our ambipolar structures reveal amphoteric charge defects that remain after annealing with charging energies of ~10 meV in both the positive and negative charge state.