The emission of silicon quantum dots is weaker when their surface is passivated well. Oxygen or nitrogen on surface of silicon quantum dot can break the passivation to form the localized electronic state in band gap to generate active center where the stronger emission occurs. In this way we can build up the radiative matter for emission. Controlling the surface bonds on silicon quantum dots, various wavelengths of emission can be obtained. The annealing is important for the treatment of the activation. Experiments demonstrate that the stimulated emissions at about 600 nm and 700 nm appear on active silicon quantum dots, and the photoluminescence peaks are found in a range from 1500 nm to 1600 nm.