Correlation between damage evolution, cluster formation and optical properties of silver implanted lithium niobate

In the present contribution results of Ag cluster synthesis in lithium niobate (LiNbO3) by ion implantation and subsequent thermal annealing are presented. Silver ions were implanted into x-cut LiNbO3 with an ion energy of 380 keV at liquid nitrogen temperature, room temperature and 700 K to an ion fluence of 1 × 1017 cm−2, respectively. Damage and cluster size distributions in the implanted layers were analyzed by means of RBS and STEM/TEM after implantation and subsequent rapid thermal annealing in the temperature range of 573–1173 K. The layers are initially amorphous after implantation at liquid nitrogen or room temperature and recrystallize from the substrate towards the surface with increasing annealing temperature. The maximum radius of the initially formed silver clusters increases from about 3 to 20 nm under rapid thermal annealing. Optical transmission measurements show a red-shift of the surface plasmon resonance (SPR) peak with increasing annealing temperature. According to the Mie scattering theory the red-shift for annealing temperatures below 873 K is most likely due to the recrystallization of amorphous LiNbO3. For even higher annealing temperatures the further red-shift is connected with the growth of the silver clusters.