InAs nanostructures grown by droplet epitaxy directly on InP(001) substrates

• InAs nanostructures were grown directly on InP by droplet epitaxy.
• We study the changes in the nanostructures on growth temperature.
• We extract values of surface diffusion energy for both <110> crystal.

This work deals with the development of growth processes by droplet epitaxy to obtain InAs quantum dots directly on InP (001) surfaces (without any InGaAs or InAlAs intermediate layer). The indium atoms for droplet formation were deposited at different substrate temperatures, TS, below 300 °C in a solid source molecular beam epitaxy system. From the evolution of the size and shape of the nanostructures with TS, values of magnitudes related with indium atoms diffusivity have been extracted. The photoluminescence signal is investigated for ensemble and single InAs nanostructures emitting around 1.3–1.5 μm. The emission properties drastically change with thermal annealing processes that improve the crystalline quality.