Electronic localization and optical absorption in embedded silicon nanograins

摘要

We study the spatial distribution of electron states in crystalline Si nanograins embedded into amorphous silicon. We prove that it is not possible to tune the absorption gap by only controlling the size of the grain, since no quantum confinement there occurs. The absorption properties of such a two-phase system are rather controlled by the population of localized electron states generated by large angular distortions of Si-Si bonds.