However, the deposition of thicker buffer layer is limited because of the poor adhesion of the lanthanum nitrate buffer layer with the underlying PVP organic film. The X-ray diffraction (XRD) measurements indicate that the films are crystallized into a pure perovskite phase, with a tetragonal geometry. It is evident from Figure 1b that no diffraction peaks are observed for the samples (buffer layer thickness 8.9 nm) annealed at 600°C, whereas it shows well-defined peaks for films annealed at 700°C. The films annealed at 600°C do not show any learn more diffraction

peaks of fresnoite or BTO, indicating the amorphous nature of the film. The peak observed around 26° correspond to La2O3. The absence of the fresnoite silicate phases also indicates that no reaction happened at the BTO/buffer layer interface due to the interdiffusion of Si. Figure 1c shows the XRD patterns of BTO thin films (annealed at 700°C) deposited on 8.9-nm-thick buffer layers that are heat-treated at 450°C or 600°C. It is obvious from the measurements that crystallization of the BTO films is influenced by the heat treatment of the buffer layer. Since the LaO(NO3) intermediate phase is only present up to 570°C, after which an non-stoichiometric unstable La(O)1.5(NO3)0.5 phase appears, it is clear that the LaO(NO3) phase exhibits

superior properties as an intermediate layer. The heat treatment influences the nucleation mechanism of the BTO film selleck inhibitor and results selleckchem in different diffraction peaks in the XRD spectrum. Crystal orientation of BTO thin film The dielectric, piezoelectric, and electro-optical properties of the thin films depend strongly on the crystal orientation. Highly c-axis-oriented BTO thin films reported before are grown on either a single-crystalline oxide substrate or with a preferentially oriented thick (>100 nm) conductive or dielectric intermediate buffer layer [13, 15]. The use of a thick buffer layer limits the performance of the ferroelectric films for certain applications (e.g., electro-optical devices). The results shown in Figure 2 indicate that we can grow highly c-axis SB-715992 price textured BTO films with LaO(NO3)

buffer layers (keeping the buffer layer thickness as 8.9 nm) by adding the number of annealing steps. Figure 2 XRD patterns obtained for BTO thin films. The films were deposited on a buffer layer with a thickness of 8.9 nm and a BTO seed layer of 30 nm (a) annealing after each 30-nm BTO layer deposition at different temperatures and (b) annealing at 700°C after each 30-nm BTO layer deposition or after four 30-nm BTO depositions (120 nm). Figure 2 shows the XRD pattern of BTO films grown on a BTO seed layer. The seed layer is prepared by depositing a thin layer (30 nm) of BTO film on the buffer layer (8.9 nm), followed by pyrolysis (350°C) and annealing (700°C). After the seed layer, either the normal procedure is followed (annealing after 120 nm of BTO is deposited) or layer-by-layer annealing is used (after each 30-nm deposition).