Structure And Luminescence Properties Of Si-nanocrystallites Produced By Electrochemically Etching

We report the Si-nanocrystallites-embedded-in-SiO2-matrix framework formed in the surface of the traditional electrochemically-produced samples after being peeled off the surface porous film in the marinade, photoluminescence (PL) and electroluminescence (EL) were used to test the samples in room temperature. SEM, TEM, AFM, XPS, FTIR were also used to characterize the structure and components of the samples.Ultraviolet-blue PL intensity was about 10 times as much as the samples before peeled off the porous film. The PL intensity got one third of the original intensity after annealed in O2 at 300 , and then got stronger along with the annealing temperature. A semitransparent gold film was evaporated on the surface of the samples to form EL devices. A stable green EL can be obtained from the samples, it got stronger along with the applied voltage, and the EL peak position did not change. The samples which was evapored a 50nm-thick carbon film had a more stronge and stable EL.The weak structure and unstable components of the porous film are responsible for the weak and unstable PL and EL. After it was pealed off fromthe samples, there formed rich Si nanocrystallites which embedded in SiO2 matrix framework in the surface. We attribute the strong and stable PL and EL to it. The model of quantum confined-luminescence centers was used to explain it.