The UV absorption edge of stoichiometric, congruent and Mg doped congruent LiNbO3 crystals was measured in the temperature range 10-300 K. The shape of the absorption edge of stoichiometric LiNbO3 was found to obey the Urbach rule reflecting the intrinsic character of the absorption. The shift of the absorption edge to longer wavelengths observed in the case of the congruent material can be, explained by the presence of localized excitons due to excess Nb situated in Li positions. The possibility of removing the excess Nb by doping the congruent material by MgO is pointed out.
ASJC Scopus subject areas
- Physics and Astronomy(all)