Single crystalline samples of bismuth tellurite
(Bi2TeO5) were implanted with 800 keV
Au+ions to a fluence of 1×1016 cm-2 at
room temperature. The samples were subjected to heat treatments in two
different ambients (air and high vacuum) at temperatures ranging from 400 -
700°C in a conventional furnace. Strong absorption maxima in the range from
600 - 630 nm in the optical absorption spectra and an intense blue-green
color in the samples were observed for annealings performed in air at
temperatures between 500 and 700°C indicating the formation of gold
colloids. The average radii of the Au clusters formed were estimated to be
in the range of 3-4 nm. Samples annealed under vacuum showed distinct
changes in color for different annealing temperatures. Studies using the
RBS/channeling technique indicate that no full recrystallization of the
samples was achieved under both annealing regimes although heat treatment
under vacuum provides a significantly better lattice recovery than for air
ambient.