Electron localization in self-assembled Si/Ge(111) quantum dots

TL;DR

This study investigates electron localization in Si/Ge quantum dot heterostructures using transport and ESR measurements, revealing localized electrons in Si QDs on Ge(111) substrates and the effects of strain and intermixing.

Contribution

It provides new insights into electron localization mechanisms in Si/Ge quantum dots, especially on Ge(111) substrates, combining ESR and transport data.

Findings

ESR signal observed with g=2.0022 indicating localized electrons

Transport measurements confirm efficient electron localization in Si QDs

Strong Ge-Si intermixing affects ESR signals in QDs on Ge(001)

Abstract

Electron localization in the Si/Ge heterosystem with Si quantum dots (QDs) was studied by transport and electron spin resonance (ESR) measurements. For Si QD structures grown on Ge(111) substrates, the ESR signal with g-factor $g=2.0022\pm0.0001$ and ESR line width $\Delta H\approx1.2$ Oe was observed and attributed to the electrons localized in QDs. The g-factor value was explained by taking into account the energy band modification due to strain effects and quantum confinement. A strong Ge-Si intermixing in QD structures grown on Ge(001) is assumed to be main reason of unobserved ESR signal from QDs. The transport behavior confirms the efficient electron localization in Si QDs.