Quantum confinement effect in SiO2 films containing Ge microcrystallites

SiO₂ thin films embedded with Ge microcrystallites (Ge-SiO₂ films) were prepared by RF-magnetron co-sputtering method from a composite target of Ge and SiO₂. The average size of Ge crystallites can be modulated by the experiment parameters. The optical absorption and non-linear optical properties of Ge-SiO₂ films were measured. The blue shift of the optical absorption edge, the saturated absorption and two-photon absorption under the condition of resonant absorption have been observed, and are discussed according to the quantum confinement effect.