Electro-optic property of ZnO:X (X = Li,Mg) thin films

We have proposed an application of ZnO:X (X = Li,Mg,Ni,Al etc.) films for monolithic optical integrated circuits (OlCs) (Mat. Res. Soc. Symp. Proc. 574 (1999) 317). Although non-doped ZnO has an electro-optic effect, it is only a Pockel's effect. The electro-optic effect of Pb(Zr,Ti)O-3 (Jpn. J. Appl, Phys. 34 (1995) 509 1) is superior to ZnO, because that is caused by a non-linear Kerr effect. Our group demonstrated that Li-doped ZnO (ZnO:Li) films exhibited ferroelectric behavior (Appl. Phys. A, in press). ZnO with ferroelectricity should have a non-linear electro-optic effect against the applied voltage. In this paper, to design the ZnO monolithic slab waveguide for electro-optical switch, the refractive indices of top and bottom electrode layers and core layer were investigated. Then, electro-optical property of ZnO:Li,Mg films was evaluated, and the possibility of applying to an optical switch was also discussed. (C) 2002 Elsevier Science B.V. All rights reserved.