Simultaneous Localization of Electrons in different Δ-valleys in Ge/Si Quantum Dot Structures

الأصل · EN

In the present work the possibility of simultaneous localization of two electrons in Δ¹⁰⁰ and Δ⁰⁰¹ valleys in ordered structures with Ge/Si(001) quantum dots (QD) was verified experimentally by the electron spin resonance (ESR) method. The ESR spectra obtained for the ordered ten-layered QD structure in the dark show the signal corresponding to electron localization in Si at the Ge QD base edges in Δ¹⁰⁰, Δ⁰¹⁰ valleys (gzz=1.9985, gin-plane=1.999). Light illumination causes the appearance of a new ESR line (gzz=1.999) attributed to electrons in the Δ⁰⁰¹ valley localized at QD apexes. The observed effect is explained by enhancement of electron confinement near the QD apex by Coloumb attraction to the photogenerated hole trapped in a Ge QD.