Band alignment switching and the interaction between neighboring silicon nanocrystals embedded in a SiC matrix
V Kocevski and O Eriksson and J Rusz, PHYSICAL REVIEW B, 91, 165429 (2015).
We present results from density functional theory study of the electronic properties of silicon nanocrystals (Si NCs) embedded in a silicon carbide (SiC) matrix, considering different combinations of various NCs and host matrix sizes. We show that the NC and the host matrix form a type-II band alignment, with the states at the top of the valence band being in the Si NC and the states at the bottom of the conduction band in the host matrix. Moreover, this band alignment can be interchanged with introducing oxygen at the interface. This interchange in the band alignment has a rather weak influence on the absorption of the system. We demonstrate that the charge densities of some valence band states can overlap with the charge densities of the neighboring NCs. We also demonstrate that this leakage of states is significant when the distance between the neighboring NCs is less than similar to 1.6 nm.
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