Optical Properties of CuCl^＋-Implantation and Observation of Sub-micrometre Particles in α-Al2O3 Crystals

Crystal samples of α-Al2O3 were implanted in different crystalline orientations with CuCl^+ at intensities from 6×10^16 ions/cm^2 to 5×10^17 ions/cm^2 and energies from 350 to 380keV at different temperatures. A strong absorption of UV section can be seen in optical absorption spectra for all of the specimens. Gaussian fitting for the absorption curves with luminescence measurements confirmed that there were point defects such as F,F^+, F2^+, and F2 centres in the CuCl^+-implanted α-Al2O3 samples. It is found that the absorption intensity is decreased by annealing treatment, thus the number of the colour centres was decreased due to annealing. It is also found that the variety of colour centre number was dependent greatly on implantation conditions, substrate orientation and annealing temperature. Sub-micrometre particles after annealing have been observed by using the SEM technique.