Raman spectra of MOCVD-grown ferroelectric PbTiO3 thin films

Abstract

Lead titanate (PbTiO3) has been grown on a variety of substrates by using the metalorganic chemical vapor deposition (MOCVD) technique. The substrates employed included Si, GaAs, MgO, fused-quartz, sapphire, and KTaO3. Raman spectra from these heterostructures are presented. All of the films exhibited the strong, narrow spectral features characteristic of PbTiO3 perovskite-oxide crystals and indicative of high crystalline quality. Temperature behaviors of the Raman modes, including the so-called `soft-mode', were studied. A `difference-Raman' technique was used to distinguish the contributions of the PbTiO3 single-crystal substrate.