Encapsulated Silicon Nanocrystals Formed in Silica by Ion Beam Synthesis

摘要

The photoluminescence(PL)emission of Si nanocrystals synthesized by 400 keV Si ion implanted in SiO_2 is studied as a function of ion dose and annealing time.The formation of nanocrystals at around 600 nm from the surface was confirmed by RBS and HRTEM,and the Si nanocrystals showed a wide and very intense PL emission at 700-900 nm.The intensity of this emission showed a typical behaviour with a fast transitory increase to reach a saturation with the annealing time,however,the red shift increased continuously because of the Ostwald ripening.The oversaturation of dose derived a decrease of PL intensity because of the diminishment of quantum confinement.A strong enhancement of PL intensity by H passivation was confirmed also,and the possible mechanism is discussed.