Nonlinear optical properties of phosphorous-doped Si nanocrystals embedded in phosphosilicate glass thin films

Nonlinear optical properties of phosphorus (P)-doped silicon (Si) nanocrystals are studied by z-scan technique in femtosecond regime at around 1.6 eV. The nonlinear refractive index (n(2)) and nonlinear absorption coefficient (beta) of Si-ncs are significantly enhanced by P-doping. The enhancement of n(2) is accompanied by the increase of the linear absorption in the same energy region, suggesting that impurity-related energy states are responsible for the enhancement of the nonlinear optical response.