Wetting layer evolution and its temperature dependence during self assembly of InAs/GaAs quantum dots

TL;DR

This study investigates how the wetting layer in InAs/GaAs quantum dots evolves with temperature, revealing unexpected behaviors linked to kinetic effects during self-assembly, using reflectance difference spectroscopy and a rate equation model.

Contribution

It introduces a rate equation model to explain the temperature-dependent evolution of the wetting layer during quantum dot self-assembly, highlighting kinetic influences.

Findings

Wetting layer thickness increases monotonically at low temperatures.

At higher temperatures, the wetting layer first increases then decreases.

Temperature dependence of quantum dot growth affects wetting layer evolution.

Abstract

For InAs/GaAs(001) quantum dot (QD) system, the wetting layer (WL) evolution and its temperature dependence were studied using reflectance difference spectroscopy (RDS) and analyzed with a rate equation model. The WL thicknesses showed a monotonic increase at relatively low growth temperatures but a first increase and then decrease at higher temperatures, which were unexpected from the thermodynamic understanding. By adopting a rate equation model, the temperature dependence of QD growth was assigned as the origin of different WL evolutions. A brief discussion on the indium desorption was also given. Those results gave hints of the kinetic aspects of QD self-assembly.