2007/10/01 by Christos S. Garoufalis, C. S. Garoufalis, Garoufalis, C. S.
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum Dots Synthesis And Properties #Semiconductor Quantum Structures and Devices #Semiconductor materials and interfaces #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.0710.0309
18 pages, 6 figures
arxiv created 2007/10/01 · openalex publication_date 2007/10/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The structural, cohesive, electronic and optical properties of mixed SiGe:H quantum dots are studied by Density Functional Theory (DFT) calculations on a representative ensemble of medium size nanoparticles of the form SixGe47-x:H60. The calculations have been performed in the framework of the hybrid non-local exchange-correlation functional of Becke, Lee, Parr and Yang (B3LYP). Besides the ground state DFT/B3LYP values we provide reliable result for the lowest spin and symmetry allowed electronic transition based on Time Dependent DFT (TDDFT/B3LYP) calculations. Our results show that the optical gap depends not only on the relative concentrations of silicon, germanium and hydrogen, but also on the relative position of the silicon and germanium shells relative to the surface of the nanocrystal. This is also true for the structural, cohesive and electronic properties allowing for possible electronic and optical gap engineering. Moreover, it is found that for the cases of nanoparticles with pure Ge or Si core, the optical properties are mainly determined by the Ge part of the nanoparticle, while silicon seem to act as a passivant.