Annealing simulations to determine the matrix interface structure of SiC quantum dots embedded in SiO2

Abstract

AbstractWe use the Density Functional based Tight‐Binding (SCC‐DFTB) method in a Quantum Mechanics/Molecular Mechanics embedding scheme to simulate single SiC quantum dots of different shapes and with diameters of up to 1 nm, embedded in a block of α ‐Quartz with cell vectors of a = 15 nm and c = 13 nm.First results show that during the annealing process three recurring motives appear at the SiC/SiO2 interface of the embedded nanocrystals: Si‐Si bonds often in Si interstitial‐like configurations, C‐C bonds involving all possible combinations of sp3 and sp2 hybridized carbon and threefold coordinated oxygen atoms. All of these defects, alone or in complexes, may play a crucial role in quenching the luminescence of these embedded nanocrystals. Detailed studies of the spectroscopic properties if the point defects identified in this work is indicated (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)