Telecom-wavelength InAs QDs with low fine structure splitting grown by droplet epitaxy on GaAs(111)A vicinal substrates

TL;DR

This paper reports the growth of InAs quantum dots on GaAs(111)A substrates via droplet epitaxy, achieving low fine structure splitting suitable for telecom-band quantum communication applications.

Contribution

It demonstrates a novel growth method for InAs quantum dots with low fine structure splitting on vicinal GaAs(111)A substrates.

Findings

Quantum dots emit at 1.3 μm telecom O-band

Fine structure splitting as low as 16 μeV

High-quality, relaxed InAlAs metamorphic layer

Abstract

We present self-assembly of InAs/InAlAs quantum dots by droplet epitaxy technique on vicinal GaAs(111)A substrates. The small miscut angle, while maintaining the symmetries imposed to the quantum dot from the surface, allows fast growth rate thanks to the presence of preferential nucleation sites at the step edges. A 100 nm InAlAs metamorphic layer with In content > 50% is already almost fully relaxed with a very flat surface. The quantum dots emit at the 1.3 {\mu}m telecom O-band with the fine structure splitting as low as 16 {\mu}eV, thus making them suitable as photon sources in quantum communication networks using entangled photons.