Evolution of self-assembled InAs/Gas(001) quantum dots grown by growth-interrupted molecular beam epitaxy

TL;DR

This study investigates the growth dynamics of self-assembled InAs/GaAs quantum dots using molecular beam epitaxy, revealing two families of QDs with distinct growth behaviors and a kinetic model describing their evolution.

Contribution

It introduces a rate-equation kinetic model that quantitatively describes the evolution of two quantum dot families during growth and interruption modes.

Findings

Small Q3D QDs decrease exponentially during interruption

Large QDs grow via Ostwald ripening

Conversion rate depends on superstress and wetting layer adatoms

Abstract

Self-assembled InAs quantum dots (QDs) grown on GaAs(001) surface by molecular beam epitaxy under continuous and growth-interruption modes exhibit two families of QDs, quasi-3D (Q3D) and 3D QDs, whose volume density evolution is quantitatively described by a rate-equation kinetic model. The volume density of small Q3D QDs decreases exponentially with time during the interruption, while the single-dot mean volume of the large QDs increases by Ostwald ripening. The kinetics of growth involves conversion of quasi-3D to 3D QDs at a rate determined by superstress and participation of the wetting layer adatoms. The data analysis excludes that quasi-3D QDs are extrinsic surface features due to inefficient cooling after growth.