Optical Properties of Epitaxial Plt Thin Films

Abstract

Metalorganic chemical vapor deposition (MOCVD) was used to prepare epitaxial or highly oriented PLT (Pb1-xLaxTiO3) thin films with x in the range of 0.21 to 0.34. The growth of PLT films resulted in three-dimensional epitaxial heterostructures on (100) surface of the MgO and the KTaO3 substrates. The PLT film grown on the KTaO3 (100) substrate has a significantly lower minimum channeling yield compared to that on the MgO (100) substrate because of the smaller lattice mismatch. The thickness and the refractive indices in the wavelength range of 435 to 1,523 nm were measured by the prism coupling method. The measured film thickness of 570 nm was in good agreement with that from RBS measurements. The refractive index of PLT film is smaller than that of PbTiO3, its difference at 632.8 nm is about 2.5 %. The dispersion of the refractive index was well fitted to a Sellmeier dispersion formula.