https://doi.org/10.1140/epjb/e2011-20153-7
Electronic structures of alloy quantum dots with nonuniform composition
Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, 100876, P.R. China
Corresponding author: a yuzhongyuan30@gmail.com
Received:
3
March
2011
Revised:
15
April
2011
Published online:
9
June
2011
In this study, the significant effect of the nonuniform composition in alloy quantum dots (QDs) on electronic structure is analyzed in depth. The equilibrium composition profiles in experimentally observed dome and barn shaped GeSi/Si QDs are determined by combining the finite element method and the method of moving asymptotes. Due to the composition variation, the total band edge of heavy hole is dominated by the band offset and spin-orbit coupling rather than the strain effect. The numerical results reveal that the wave function of heavy hole trends to be localized in the Ge-rich region at the top of the large QD. Moreover, the size effect gradually compensates the composition effect as the size of QD decreases.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2011
