F. Naab

Formation of Carbon‐based Nanocrystal using Low Energy Carbon Ion Implantation into Silica

Carbon‐based nanocrystals, formed in silica by low‐energy carbon implantation and subsequent thermal annealing, have been previously reported, but ambiguities as to the equilibrium morphology and its relationship to the source of photo luminescence. In our study, silica samples were implanted with 2.0×1017 atoms/cm2 C− ions at energies of 8.5 keV, 40 keV and 70 keV. Samples were annealed for 15, 30, 60, 120, 240 minutes at 1100° C in a forming gas (4%H2+96%Ar). Rutherford backscattering (RBS), particle induced x‐ray emission (PIXE), and photoluminescence (PL) were used to characterize the nanocrystals formed by these conditions. The resulting photoluminescence analysis indicated that the size distribution of the nanocrystals could be tailored to yield a broad spectral output between 2.0–2.8 eV by controlling the formation parameters. Also a few notable factors, such as liberation of oxygen in the silica during implantation, as well as uptake of ambient oxygen in the annealing furnace, will be shown to pla...