Different quantum behavior of the E(1) and E(2) spectral structures in Ge nanocrystals

In this paper we report absorption measurements in the range 0.6-6.0 eV, performed at 77 K on Ge nanocrystals grown by a self-organization process applied to a semiconductor. Evidence of a relevant blueshift a of E(2) and weakening of E(1) with Size reduction is obtained. This behavior is interpreted in terms of quantum confinement in connection with the different nature of the two structures.