X-RAY PHOTOELECTRON-SPECTROSCOPY STUDY OF CU IMPLANTED IN LINBO3

Cu+ ions were implanted into LiNbO3 with doses of 3×1016–5.7×1016 ions/cm2 at an energy of 30 keV. The LiNbO3 implanted with Cu+ ions showed a blue-green color. Optical absorption spectra and XPS (X-ray photoelectron spectroscopy) valence-band spectra were measured for as-implanted and annealed samples. The absorption peak at ∼640 nm was decreased by annealing at relatively low temperatures of 150∼200°C. It was found that upon annealing, while no apparent change in the binding energy of Cu2p3/2 was observed, the peak position of Cu3d was slightly shifted to higher binding energy and the full width at half maximum of the peak was slightly narrowed compared to that of the as-implanted samples. This change in the valence-band spectrum may be due to variation of the electronic state of Cu3d related to the colorations. © 1990 The Japan Society of Applied Physics.