Creation of Novel Quantum Dot embedded in Glasses by Ion Implantation and Their Optical Properties

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The purposes of this research project are to create novel quantum dot embedded in oxide glasses by ion implantation and to examine the optical properties of the resulting materials. The results obtained are summarized as follows :(1) Dual structure nano sized colloid particles (Cu core and a Cu_2O shell) embedded in glasses have been created by sequential implantation of Cu ions followed by F ions in amorphous silica. Although the presence of nanosized clusters and electron diffraction patterns indexed as Cu were observed by TEM observation, no Cu plasmon band which should appear at-2eV was perceived.(2) A striking difference in results from different implantation sequences, the optical absorption spectra and structure of nanosized colloid particles formed by changing the implantation sequence of Cu and F ions. The difference is explained in terms of a model combining energy depositions with chemical interactions of implanted F ions with ions an amorphous SiO_2.(3) Nanometer-sized crystalline Ge colloid particles have been formed by implantation of protons into substrate glasses having a composition of 1GeO_2-9SiO_2 to a fluence of 1x10^<18> cm^<-2> at an energy of 1.5 MeV at toom temperature without post-thermal annealing. Intensities of the absorption band due to Ge particles reach a maximum at-30mum from the surface and their depth profile is close to that of the electronic energy loss.(4) The primary facor controlling Cu-colloid formation in the mplanted glasses is not the change in the continuity of silica network structure but change in the strength of solvation of charged states of implanted ions.