Dependence of the optical gap of Si quantum dots on the dot size

The dependence of the optical gap of Si quantum dots, embedded in a SiO2 insulator host, on the dot size was calculated in terms of an envelope-function approximation. It is shown that consideration of the finiteness of the SiO2 band gap and an abrupt change in the effective mass at the Si-SiO2 interface significantly decreases the optical gap of quantum dots in comparison with a model in which the potential barriers for electrons and holes are assumed to be infinitely high. The obtained results are in good agreement with the experimental data. (C) 2002 MAIK "Nauka / Interperiodica".