Equilibrium shapes and energies of coherent strained InP islands

TL;DR

This study models the equilibrium shapes and energies of coherent strained InP islands on GaP using a hybrid approach, combining density functional theory and continuum elasticity, aligning well with experimental data.

Contribution

It introduces a hybrid computational method to predict equilibrium shapes of InP islands, incorporating surface and bulk energies, and compares results with experimental observations.

Findings

Equilibrium shapes include {101}, {111}, {ar{1}ar{1}ar{1}} facets and a (001) top surface.

Calculated shapes align well with atomic-force microscopy data.

Discussion on Ostwald ripening and strain fields in capped vs. uncapped islands.

Abstract

The equilibrium shapes and energies of coherent strained InP islands grown on GaP have been investigated with a hybrid approach that has been previously applied to InAs islands on GaAs. This combines calculations of the surface energies by density functional theory and the bulk deformation energies by continuum elasticity theory. The calculated equilibrium shapes for different chemical environments exhibit the {101}, {111}, {\=1\=1\=1} facets and a (001) top surface. They compare quite well with recent atomic-force microscopy data. Thus in the InP/GaInP-system a considerable equilibration of the individual islands with respect to their shapes can be achieved. We discuss the implications of our results for the Ostwald ripening of the coherent InP islands. In addition we compare strain fields in uncapped and capped islands.