부산대학교 도서관

The erbium incorporation into LiNbO[sub 3] by diffusion doping is investigated in detail by means of Secondary Ion Mass Spectrometry, Secondary Neutral Mass Spectrometry, Rutherford Backscattering, Atomic Force Microscopy, X-ray Standing Wave technique and optical site-selective spectroscopy. The diffusion of erbium in LiNbO[sub 3] can be described by Fick’s laws of diffusion with a concentration-independent diffusion coefficient. The diffusion constants and activation energies for Z-cut (X-cut) LiNbO[sub 3] are 4.8×10[sup -5] cm[sup 2] /s (12.0×10[sup -5] cm[sup 2] /s) and 2.28 eV (2.44 eV), respectively. A limited solubility of erbium in LiNbO[sub 3] has to be taken into account increasing exponentially with rising temperature. During the first step of diffusion an Er[sub x] Nb[sub y] -oxide layer is formed at the surface of the sample acting as diffusion reservoir. Erbium is incorporated into LiNbO[sub 3] on vacant Li-sites slightly shifted from the original Li-position along the (-c)-direction. Site-selective spectroscopy found four distinguishable energetically different erbium centres at this lattice site resulting from locally different symmetries of the crystal field. [ABSTRACT FROM AUTHOR]