Integration of perovskite PZT thin films on diamond substrate without buffer layer

Abstract: In the present work, thin ZnO layers were synthesized by the sol–gel method with subsequent spin-coating on Si(100). We show that the detailed analysis of lab-recorded photoemission spectra in combination with Kelvin probe data yielded the work function, ionization energy, and valence band – Fermi level separation – and hence enabled the construction of band diagrams of the examined layers. With small modifications in preparation, very different films can be obtained. One set shows a homogeneous depth-dependent n carrier distribution, and another a significant carrier concentration gradient from n-type conductivity to almost metal-like n+ character. Likewise, the surface morphology can be tuned from a uniform, compact surface with spherical single-nm sized grain-like features to a structured surface with 5–10 nm tall crystallites with (002) dominating crystal orientation. Based on the band-bending and the energy levels observed, defects of contradictory nature, i.e. acceptor–donor–trap (ADT) properties, were identified. These defects may be groups of point defects, with opposite character. The ADT states affect the energy levels of the oxide layers and due to their nature cannot be considered in the photoemission experiment as mutually independent. The versatile nature of the synthesis provides us with the opportunity to tune the properties with a high degree of freedom, at low processing costs, yielding layers with an exotic electronic structure. Such layers are interesting candidates for applications in photovoltaic and nanoelectronic devices.

Abstract: In this study, we have investigated 1–3 story structured piezoelectric energy harvesters based on lead zirconate titanate (PZT) multi-layered actuators. These piezoelectric energy harvesters were fabricated using Pb(Zr,Ti)O 3 based ceramic actuators. The multi-layered PZT actuators were based on green sheets that were prepared by a tape casting process. The ceramic actuators were attached on metallic electrodes with poled states. The structures were filled with polydimethylsiloxane (PDMS). The multi-layered piezoelectric energy harvesters were stacked as single-story structured, double-story structured, and triple-story structured devices, respectively. Generated output voltages, stored power, and maximum output power with various loads of the piezoelectric energy harvesters with various story structures were analyzed.

Abstract: We obtained an atomically flat diamond surface following dressed photon–phonon (DPP) etching using 3.81 eV light and O2 gas. We obtained a surface roughness (Ra) of 0.154 nm for Ib-type (1 1 1) diamond and 0.096 nm for Ib-type (1 0 0) diamond. To evaluate the surface roughness, we grouped the surface into bins of width l and introduced the standard deviation of the height difference function for a given separation l, which allowed us to determine the height variation of the surface. Based on the calculation of standard deviation, the conventional adiabatic photochemical reaction did not remove the small surface features, while DPP etching decreased the surface roughness for all length scales.

Abstract: Metallic implants such as hip and knee often fail due to the combined action of wear and corrosion Nanocrystalline diamond (NCD) coatings on metallic implants can be a potential candidate to overcome this issue In this work, we investigated the tribocorrosion and electrochemical behaviour of Nanocrystalline Diamond (NCD) Coatings deposited on Cp-Ti, Ti-6Al-4V and Ti-13Nb-13Zr using hot filament chemical vapour deposition (HFCVD) technique The results demonstrate that the factors such as intercrystallite pores, TiC interlayer, and electrical conductivity influenced the electrochemical behaviour of all the NCD coatings Under tribocorrosion, an unexplainable shift in the open circuit potential (OCP) was noticed at the initiation of sliding Further, a continuous decrease in OCP was also observed as the sliding progress

Abstract: The peak near 1150 cm 21 in the visible Raman spectra of poor quality chemical-vapor-deposited diamond is often used as the signature of nanocrystalline diamond. We argue that this peak should not be assigned to nanocrystalline diamond or other sp-bonded phases. Its wave number disperses with excitation energy, its intensity decreases with increasing excitation energy, and it is always accompanied by another peak near 1450 cm, which acts similarly. This behavior is that expected for sp-bonded configurations, with their smaller band gap. The peaks are assigned to transpolyacetylene segments at grain boundaries and surfaces.

Abstract: Photons have many advantages for vaporizing condensed systems, and laser vaporization sources have a flexibility not available with other methods. These sources are applied to making thin films in the well-known technique of pulsed laser deposition (PLD). The vaporized material may be further processed through a pulsed secondary gas, lending the source additional degrees of freedom. Such pulsed-gas sources have long been exploited for fundamental studies, and they are very promising for film deposition, as an alternative to chemical vapor deposition or molecular beam epitaxy. The authors outline the fundamental physics involved and go on to discuss recent experimental findings.

Abstract: The first- and second-order Raman spectra of diamond were studied using the 4880 \AA{} and 5145 \AA{} lines of an Ar ion laser and the 6328 \AA{} line of a He-Ne laser. The spectra were recorded at room, liquid-nitrogen, and liquid-helium temperatures. In addition to the second-order spectrum previously reported by Krishnan, a new weaker second-order spectrum was observed in the range 1600-2100 ${\mathrm{cm}}^{\ensuremath{-}1}$. Polarization studies were carried out on both the first- and second-order spectra. From such studies it was established that the 1332-${\mathrm{cm}}^{\ensuremath{-}1}$ Raman line is the zone-center optical phonon with ${\ensuremath{\Gamma}}^{(25+)}$ (${F}_{2g}$) symmetry. The prominent features in both the second-order Raman spectra reported here and the second-order infrared spectra are interpreted in terms of the critical points of the phonon dispersion curves established from neutron spectroscopy and on the basis of space-group selection rules.

Abstract: A two-step seeding process has been developed to lower the transformation temperature and modify the grain structure of ferroelectric lead zirconate titanate (PZT) thin films with high Zr/Ti ratio. Previous study has shown that nucleation is the rate-limiting step for the perovskite formation. Therefore, any process that enhances the kinetics of nucleation is likely to decrease the transformation temperature. In this process, a very thin (45 nm) seeding layer of PbTiO3, which has a low effective activation energy for perovskite formation, was used to provide nucleation sites needed for the low temperature perovskite formation. In this study, we have shown that the pyrochlore-to-perovskite phase transformation temperature of PbZrxTi1−xO3 films of high Zr/Ti ratio (e.g., x = 53/47) can be lowered by as much as 100 °C. The grain size of these films can also be substantially modified by this two-step approach.

Abstract: It is shown that Raman scattering from polycrystalline piezoelectric solids contains all of the essential features of Raman single-crystal spectra even when the crystal spectrum is quite anisotropic As an illustration of the Raman powder technique, the ceramic ferroelectric-antiferroelectric system PbTi${\mathrm{O}}_{3}$-PbZr${\mathrm{O}}_{3}$ has been investigated and the "soft" $E(\mathrm{TO})$ optical phonon modes measured in the tetragonal ferroelectric region