Dedicated to Thomas Frauenheim on the occasion of his 60th birthday
Identification of defects at the interface between 3C-SiC quantum dots and a SiO2 embedding matrix
Article first published online: 23 DEC 2011
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
physica status solidi (b)
Volume 249, Issue 2, pages 360–367, February 2012
How to Cite
Vörös, M., Gali, A., Kaxiras, E., Frauenheim, T. and Knaup, J. M. (2012), Identification of defects at the interface between 3C-SiC quantum dots and a SiO2 embedding matrix. Phys. Status Solidi B, 249: 360–367. doi: 10.1002/pssb.201100527
- Issue published online: 19 JAN 2012
- Article first published online: 23 DEC 2011
- Manuscript Revised: 14 OCT 2011
- Manuscript Accepted: 14 OCT 2011
- Manuscript Received: 31 AUG 2011
- quantum dots;
Due to the favorable band offsets, SiC nanoparticles embedded in silica form a very interesting quantum dot (QD) system. It is possible to produce such QDs in a simple oxidation–carbonization–reoxidation process on Si wafers. This could thus enable production of Si based LED integrated into Si logic devices. However, the luminescence of these QDs, is quenched. This is attributed to defect-mediated recombination of electron–hole pairs, most probably at the SiC/SiO2 interface. We present tight-binding simulated annealing calculations, in order to construct models of SiC QDs in SiO2, with the aim of obtaining an overview of the possible defects at the SiC/SiO2 interface. We identify a number of recurring interface defects which can be attributed to C or Si rich conditions or general lattice mismatch relaxation. Similar to defects have been shown to be electrically active at the SiC/SiO2 interface in MOS structures. We find evidence for strained Si–Si bonds, which can act as recombination centers in isolated SiC QDs. The defect classes identified in this work can serve as the basis for future, high precision simulations of their electronic structure.
A 66-atom spherical SiC nanocrystal with a shell of SiO2 including –OH termination (66-sph-1 cluster, only QM zone shown; cf. Fig. 2 for key).