Study of Growth Properties of InAs Islands on Nucleation Sites Defined by Focused Ion Beam

TL;DR

This study investigates how focused ion beam-created templates influence the growth, morphology, and crystalline properties of InAs islands on InP substrates, revealing dose-dependent effects on island coherence and density.

Contribution

It introduces a model linking surface potential and adatom flow to explain growth variations on FIB-patterned templates.

Findings

Low ion doses produce mainly coherent islands.

High ion doses lead to incoherent islands with higher density.

Morphologies result from coarsening and coalescence competition.

Abstract

This work describes morphological and crystalline properties of the InAs islands grown on templates created by focused ion beam (FIB) on indium phosphide (InP) substrates. Regular arrangements of shallow holes are created on the InP (001) surfaces, acting as preferential nucleation sites for InAs islands grown by Metal-Organic Vapor Phase Epitaxy. Ion doses ranging from $10^{15}$ to $10^{16}$ $Ga^{+}$/$cm^{2}$ were used and islands were grown for two sub-monolayer coverages. We observe the formation of clusters in the inner surfaces of the FIB produced cavities and show that for low doses templates the nanostructures are mainly coherent while templates created with large ion doses lead to the growth of incoherent islands with larger island density. The modified island growth is described by a simple model based on the surface potential and the net adatom flow to the cavities. We observe that obtained morphologies result from a competition between coarsening and coalescence mechanisms.