Polarized Raman Analysis at Low Temperature to Examine Interface Phonons in InAs/GaAs_(1-x)Sb_x Quantum Dot Heterostructures

TL;DR

This study uses low-temperature polarized Raman scattering to analyze interface phonons in InAs/GaAsSb quantum dot heterostructures, revealing how Sb-content influences phonon modes through strain effects and quantum dot size.

Contribution

It provides new experimental insights into interface phonons and their dependence on Sb-content in quantum dot heterostructures, supported by strain simulations.

Findings

Sb-content affects phonon frequency shifts.

Strain relaxation influences phonon modes.

Quantum dot size impacts phonon behavior.

Abstract

An experimental study of optical phonon modes, both normal and interface (IF) phonons, in bilayer strain-coupled InAs/GaAs_(1-x)Sb_x quantum dot heterostructures has been presented by means of low-temperature polarized Raman scattering. The effect of Sb-content on the frequency positions of these phonon modes has been very well correlated with the simulated strain. The Raman peaks show different frequency shifts in the heterostructure with varying Sb-content in the capping layer. This shift is attributed to the strain relaxation, bigger size of quantum dots and type-II band alignment.