Modifications In Structure And Optical Properties Of SiO₂and Si By Cu And/or Zn Ion Implantation

Due to the control over the energy and fluence of ions, ion implantation is one ofimportant ways to synthesize composites involved nanoparticles (NPs). Thesenanocomposites have potential applications in various fields, such as opto-electronicdevices, optical switches, biosensors, etc. In this dissertation, we analysed themodifications on the structure and optical properties of SiO2and Si by Cu and/or Znion implantation. The main contents and results are given as follows:(1) At room temperature, Cu NPs were fabricated in SiO2by45keV Cu ionimplantation to a fluence of1.0×1017ions/cm2, and were then irradiated by50keV Znions to a fluence of1.0×1016ions/cm2. The prepared samples were subjected to furnaceannealing in oxygen ambient at different temperatures. The modifications in structureand optical properties of Cu NPs have been investigated in detail. Our results clarlyshow that post Zn ion irradiation could induce significant enhancement of Cu SPRabsorption. The oxidation of Cu NPs was suppressed with Zn ion irradiation. Thephotoluminesence peak around540nm was detected from the sample after400°Cannealing, which could be attributed to the excitation of Cu+. The ionization of Cuatoms was suppressed with Zn ion irradiation. After the sample was irradiated by Znions to a fluence of1.0×1016ions/cm2together with subsequent400°C annealing for1.0h, the SPR peak of Cu NPs vanished while the absorption band of CuO NPs wasobserved, indicating the oxidation of Cu NPs. The diffusion of oxygen was promotedby defects which were produced by Zn ion irradiation.(2) The samples containing Cu NPs were irradiated with50keV Zn ions tofluences of5×1015and1×1016ions/cm2, and were then subjected to furnace annealingtemperatures ranging from400°C to600°C for1.0h in nitrogen ambient. Themodification in photoluminesce properties of Cu NPs has been investigated with Znion irradiation. A clear emission band of Cu+at540nm has been observed after500°Cannealing for all samples. However, the intensity of Cu+emission band was the lowestafter Zn ion irradiation to a fluence of1.0×1016ions/cm2. The ionization of Cu atomswas suppressed with Zn ion irradiation. Owing to the fact that the diffusion of oxygenin SiO2can drive the diffusion of Cu atoms, more Cu atoms can translate into Cu+inSiO2. Thus, the intensity of Cu+emission band with400°C annealing in nitrogenambient was lower than that with400°C annealing in oxygen ambient.(3) Cz n-type crystalline Si(100) wafers were implanted with45keV Zn ions to a fluence of1.0×1017ions/cm2. Surface nanostructures on Zn ion implanted crystallineSi and their thermal evolution after annealing at different atmospheres wereinvestigated. The results indicate that the growth of Zn NPs was faster annealing atnitrogen ambient than oxygen ambient. The homelike nanostructures were detectedafter annealing at nitrogen ambient together with subsequent600°C annealing inoxygen ambient. However, the surface structures liking winding patterns were formedafter800°C annealing in oxygen ambient due to the formation of Zn2SiO4.