Showing papers on "Pulsed laser deposition published in 2017"
TL;DR: It is revealed that the potentially very high activity of the LSC surface can be traced back to few very active sites, suggesting that active sites are strongly related to Co being present at the surface.
Abstract: Improvement of solid oxide fuel cells strongly relies on the development of cathode materials with high catalytic activity for the oxygen reduction reaction. Excellent activity was found for perovskite-type oxides such as La1-xSrxCoO3-δ (LSC), but performance degradation, probably caused by surface composition changes, hinders exploitation of the full potential of LSC. This study reveals that the potentially very high activity of the LSC surface can be traced back to few very active sites. Already tiny amounts of SrO, for example, 4% of a monolayer, deposited on an LSC surface, lead to severe deactivation. Co, on the other hand, causes (re-)activation, suggesting that active sites are strongly related to Co being present at the surface. These insights could be gained by a novel method to measure changes of the electrochemical performance of thin film electrodes in situ, while modifying their surface: impedance spectroscopy measurements during deposition of well-defined fractions of monolayers of Sr-, Co- and La-oxides by single laser pulses in a pulsed laser deposition chamber.
141 citations
TL;DR: Si-doped Ga2O3 thin films were fabricated by pulsed laser deposition on semi-insulating (010) and (0001) Al 2O3 substrates in this paper, showing single crystal, homoepitaxial growth as determined by high resolution transmission electron microscopy and x-ray diffraction.
Abstract: Si-doped Ga2O3 thin films were fabricated by pulsed laser deposition on semi-insulating (010) β-Ga2O3 and (0001) Al2O3 substrates. Films deposited on β-Ga2O3 showed single crystal, homoepitaxial growth as determined by high resolution transmission electron microscopy and x-ray diffraction. Corresponding films deposited on Al2O3 were mostly single phase, polycrystalline β-Ga2O3 with a preferred (20 1 ¯ ) orientation. An average conductivity of 732 S cm−1 with a mobility of 26.5 cm2 V−1 s−1 and a carrier concentration of 1.74 × 1020 cm−3 was achieved for films deposited at 550 °C on β-Ga2O3 substrates as determined by Hall-Effect measurements. Two orders of magnitude improvement in conductivity were measured using native substrates versus Al2O3. A high activation efficiency was obtained in the as-deposited condition. The high carrier concentration Ga2O3 thin films achieved by pulsed laser deposition enable application as a low resistance ohmic contact layer in β-Ga2O3 devices.
114 citations
TL;DR: In this article, the authors demonstrate that the crystallinity, transparency, and electrical properties of NiO films are well controlled by pulsed laser deposition, which determines the photovoltaic performance of CH3NH3PbI3−xClx-based perovskite solar cells with NiO film as the hole transport layers.
Abstract: Pulsed laser deposition (PLD) is a powerful growth technique for thin films, where in situ doping and post-thermal annealing are the most effective ways to tune the crystalline and physical properties of the deposited films. This paper demonstrates that the crystallinity, transparency, and electrical properties of NiO films are well controlled by PLD, which determines the photovoltaic performance of CH3NH3PbI3−xClx-based perovskite solar cells with NiO films as the hole transport layers (HTLs). After post-annealing, the NiO films exhibit enhanced in-plane crystal orientation, high transmittance, and uniform surface morphology, and, accordingly, the power conversion efficiency (PCE) of the perovskite solar cell improves from 5.38% to 12.59%. Moreover, by doping the ablated target with lithium (Li), PLD can produce doped NiO:Li films with significantly enhanced electrical conductivity, which further improves the perovskite cell PCE from 12.59% to 15.51%. These results highlight the importance of optimizing the transporting layer properties toward high-performance inverted perovskite planar solar cells.
114 citations
TL;DR: In this article, a detailed characterization of garnet-type Li-ion conducting Li7La3Zr2O12 (LLZO) solid electrolyte thin films grown by novel CO2-laser assisted chemical vapor deposition (LA-CVD) is reported.
Abstract: The detailed characterization of garnet-type Li-ion conducting Li7La3Zr2O12 (LLZO) solid electrolyte thin films grown by novel CO2-laser assisted chemical vapor deposition (LA-CVD) is reported. A deposition process parameter study reveals that an optimal combination of deposition temperature and oxygen partial pressure is essential to obtain high quality tetragonal LLZO thin films. The polycrystalline tetragonal LLZO films grown on platinum have a dense and homogeneous microstructure and are free of cracks. A total lithium ion conductivity of 4.2·10−6 S·cm−1 at room temperature, with an activation energy of 0.50 eV, is achieved. This is the highest total lithium ion conductivity value reported for tetragonal LLZO thin films so far, being about one order of magnitude higher than previously reported values for tetragonal LLZO thin films prepared by sputtering and pulsed laser deposition. The results of this study suggest that the tetragonal LLZO thin films grown by LA-CVD are applicable for the use in all-solid-state thin film lithium ion batteries.
85 citations
TL;DR: In this paper, a comparative review of the memristive properties of ZnO thin films grown by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), and sol-gel methods is proposed.
Abstract: ASBTRACTZinc Oxide (ZnO) thin films have been addressed as promising candidates for the fabrication of Resistive Random Access Memory devices, which are alternative to conventional charge-based flash memories. According to the filamentary conducting model and charge trapping/detrapping theory developed in the last decade, the memristive behavior of ZnO thin films is explained in terms of conducting filaments formed by metallic ions and/or oxygen vacancies, and their breaking through electrochemical redox reactions and/or recombination of oxygen vacancies/ions. A comparative review of the memristive properties of ZnO thin films grown by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), and sol-gel methods is here proposed. Sputtered ZnO thin films show promising resistive switching behaviors, showing high on/off ratios (10–104), good endurance, and low operating voltages. ALD is also indicated to be useful for growing conformal ZnO layers with atomic thickness control, resulting in ...
85 citations
28 Apr 2017
TL;DR: In this article, contact metals (Au, Ir, and Cr) are deposited on bulk WSe2 under UHV and HV conditions and subsequently characterized with x-ray photoelectron spectroscopy (XPS) to elucidate the effects of reactor base pressure on resulting interface chemistry and band alignment.
Abstract: Contact metals (Au, Ir, and Cr) are deposited on bulk WSe2 under ultra-high vacuum (UHV, 1 × 10−9 mbar) and high vacuum (HV, 5 × 10−6 mbar) conditions and subsequently characterized with x-ray photoelectron spectroscopy (XPS) to elucidate the effects of reactor base pressure on resulting interface chemistry, contact chemistry, and band alignment. Au forms a van der Waals interface with WSe2 regardless of deposition chamber ambient. In contrast, Ir and Cr form a covalent interface by reducing WSe2 to form interfacial metal selenides. When Cr is deposited under HV conditions, significant oxygen incorporation is observed resulting in the thermodynamically favorable formation of tungsten oxyselenide and a substantial concentration of Cr x O y . Regardless of contact metal, WO x (2.63 < x < 2.92) forms during deposition under HV conditions which may positively affect interface transport properties. Cr and Ir form unexpectedly large electron and hole Schottky barriers, respectively, when deposited under UHV conditions due to interfacial reactions that contribute to anomalous band alignment. These results reveal the true interface chemistry formed between metals and WSe2 under UHV and HV conditions and demonstrate the impact on the Fermi level position following contact formation on WSe2.
85 citations
TL;DR: The results suggest that the strain tuning induced by AZO buffer provides an effective approach for tuning Tc of VO2 continuously.
Abstract: Vanadium dioxide (VO2) thin films with controlled thicknesses are deposited on c-cut sapphire substrates with Al-doped ZnO (AZO) buffer layers by pulsed laser deposition. The surface roughness of AZO buffer layers is varied by controlling oxygen pressure during growth. The strain in the VO2 lattice is found to be dependent on the VO2 thickness and the VO2/AZO interface roughness. The semiconductor-to-metal transition (SMT) properties of VO2 thin films are characterized and the transition temperature (Tc) is successfully tuned by the VO2 thickness as well as the VO2/AZO interface roughness. It shows that the Tc of VO2 decreases with the decrease of film thickness or VO2/AZO interface roughness. Other SMT properties of the VO2 films are maintained during the Tc tuning. The results suggest that the strain tuning induced by AZO buffer provides an effective approach for tuning Tc of VO2 continuously.
81 citations
TL;DR: The diffusion profiles can be quantitatively explained by the existence of fast oxygen ion diffusion along threading dislocations that is faster by up to 3 orders of magnitude compared to that in LSM bulk.
Abstract: Revealing whether dislocations accelerate oxygen ion transport is important for providing abilities in tuning the ionic conductivity of ceramic materials. In this study, we report how dislocations affect oxygen ion diffusion in Sr-doped LaMnO3 (LSM), a model perovskite oxide that serves in energy conversion technologies. LSM epitaxial thin films with thicknesses ranging from 10 nm to more than 100 nm were prepared by pulsed laser deposition on single-crystal LaAlO3 and SrTiO3 substrates. The lattice mismatch between the film and substrates induces compressive or tensile in-plane strain in the LSM layers. This lattice strain is partially reduced by dislocations, especially in the LSM films on LaAlO3. Oxygen isotope exchange measured by secondary ion mass spectrometry revealed the existence of at least two very different diffusion coefficients in the LSM films on LaAlO3. The diffusion profiles can be quantitatively explained by the existence of fast oxygen ion diffusion along threading dislocations that is ...
79 citations
TL;DR: In this paper, a 5.2% efficiency Cu 2 ZnSnS 4 (CZTS) solar cell made by pulsed laser deposition (PLD) featuring an ultra-thin absorber layer (less than 450nm) is presented.
78 citations
TL;DR: High-quality single-crystalline CaMnO3 films are synthesized with systematically varying oxygen vacancy defect formation energies as controlled by coherent tensile strain to demonstrate a novel pathway to control and stabilize oxygen vacancies in complex transition-metal oxide thin films.
Abstract: We demonstrate a novel pathway to control and stabilize oxygen vacancies in complex transition-metal oxide thin films. Using atomic layer-by-layer pulsed laser deposition (PLD) from two separate targets, we synthesize high-quality single-crystalline CaMnO3 films with systematically varying oxygen vacancy defect formation energies as controlled by coherent tensile strain. The systematic increase of the oxygen vacancy content in CaMnO3 as a function of applied in-plane strain is observed and confirmed experimentally using high-resolution soft X-ray absorption spectroscopy (XAS) in conjunction with bulk-sensitive hard X-ray photoemission spectroscopy (HAXPES). The relevant defect states in the densities of states are identified and the vacancy content in the films quantified using the combination of first-principles theory and core–hole multiplet calculations with holistic fitting. Our findings open up a promising avenue for designing and controlling new ionically active properties and functionalities of com...
78 citations
TL;DR: A systematic study of the fatigue mechanism of yttrium-doped hafnium oxide (HYO) ferroelectric thin films deposited by pulsed laser deposition and domain wall pinning caused by carrier injection at shallow defect centers is found to be the major fatigue mechanism.
Abstract: Owing to their prominent stability and CMOS compatibility, HfO2-based ferroelectric films have attracted great attention as promising candidates for ferroelectric random-access memory applications. A major reliability issue for HfO2 based ferroelectric devices is fatigue. So far, there have been a few studies on the fatigue mechanism of this material. Here, we report a systematic study of the fatigue mechanism of yttrium-doped hafnium oxide (HYO) ferroelectric thin films deposited by pulsed laser deposition. The influence of pulse width, pulse amplitude and temperature on the fatigue behavior of HYO during field cycling is studied. The temperature dependent conduction mechanism is characterized after different fatigue cycles. Domain wall pinning caused by carrier injection at shallow defect centers is found to be the major fatigue mechanism of this material. The fatigued device can fully recover to the fatigue-free state after being heated at 90 °C for 30 min, confirming the shallow trap characteristic of the domain wall pinning defects.
TL;DR: The structural, optical, and electrical properties of zinc oxide (ZnO) layers manufactured at different process conditions were investigated and it was shown that the type of films conductivity is metallic and it is limited by charge transfer across grain boundaries.
Abstract: The structural, optical, and electrical properties of zinc oxide (ZnO) layers manufactured at different process conditions were investigated. ZnO epitaxial layers were grown on silicon, glass, and ITO/glass substrates by pulsed laser deposition (PLD) technique. The influence of power beam, substrate temperature, and deposition time on films properties was analysed. Morphological features of the film surface were investigated by scanning electron microscopy. A structural study shown planar orientation of films at low temperatures of substrate, but the columnar type of growth originated in temperature enhances. Electrical properties were determined in the temperature range 300–500 K. It was shown that the type of films conductivity is metallic and it is limited by charge transfer across grain boundaries.
TL;DR: In this article, a core-shell nanorods (NRs) heterostructures were fabricated and their sensing performance was optimized by controlling the shell thickness based on Debye length.
Abstract: Metal oxide semiconductor (MOS) based gas sensors for triethylamine (TEA) are anticipated with low operating temperature, high response, and robust manufacturing process. TEA sensors with the α-Fe2O3@NiO or α-Fe2O3@CuO core-shell nanorods (NRs) heterostructure are successfully fabricated and their sensing performance is optimized by controlling the shell thickness based on Debye length. Porous α-Fe2O3 NRs are directly prepared on flat Al2O3 substrates by convenient hydrothermal process. The p-type shell layer is deposited by pulsed laser deposition (PLD) method, which width is controlled by changing the applied laser pulses. Due to the formation of PN heterojunction, the core-shell NR heterostructures show enhanced performances than pristine α-Fe2O3 NRs at near room-temperature, e.g. 40 °C. Moreover, such heterostructural sensor performances also exhibit a strong dependence on the shell thickness. When the p-type shell thickness is close to its Debye length (λd), the core-shell sensor of the highest response is realized. The enhanced sensing properties of this core-shell NR heterostructure toward TEA can be explained by the increase of initial resistance (Ra) due to the modulation of depletion layer through optimizing the p-type shell thickness.
TL;DR: In this article, the authors presented theoretical and experimental investigations of quantum-sized (3/3 ) Pt/Pd bimetallic core-shell nanoparticle (NP)-decorated ZnO nanorod (NR) clusters for accelerated hydrogen (H2) gas detection.
Abstract: This paper presents theoretical and experimental investigations of quantum-sized (3/3 nm) Pt/Pd bimetallic core-shell nanoparticle (NP)-decorated ZnO nanorod (NR) clusters (Pt/Pd-ZnO NRs) on silicon (Si) substrate for accelerated hydrogen (H2) gas detection. Quantum-size core–shell NP synthesis, metal loading, and Pt/Pd bimetal composition were all carefully controlled by varying the deposition conditions used in the pulsed laser deposition (PLD) system. Theory suggests that the structural arrangement of bimetallic Pt shell around a Pd core can be advantageous in H2 sensing compared to the converse arrangement. Experimental analysis showed that the as-fabricated sensor exhibited a high response magnitude of 58% (10,000 ppm), a fast response time of 5 s, and a broad detection range from 0.2 to 40,000 ppm at the operating temperature of 100 °C. The fabricated sensor also exhibited a good selectivity and a negligible humidity effect over the entire detection range. The superior sensing features of the sensor can be attributed to the enhancement of hydrogen-induced changes in the work function of the Pt/Pd-ZnO NR network. More importantly, the atomic arrangements and chemical potentials of the core–shell interfacial region play vital role in accelerating the H2 sensing properties.
TL;DR: In this paper, the authors reported the realization of epitaxial Y3Fe5O12 (YIG) thin films with perpendicular magnetic anisotropy (PMA) by pulsed laser deposition.
Abstract: Here, we report the realization of epitaxial Y3Fe5O12 (YIG) thin films with perpendicular magnetic anisotropy (PMA) The films are grown on the substituted gadolinium gallium garnet substrate (SGGG) by pulsed laser deposition It was found that a thin buffer layer of Sm3Ga5O12 (SmGG) grown on top of SGGG can suppress the strain relaxation, which helps induce a large enough PMA to overcome the shape anisotropy in YIG thin films The reciprocal space mappings analysis reveals that the in-plane strain relaxation is suppressed, while the out-of-plane strain relaxation exhibits a strong dependence on the film thickness We found that the PMA can be achieved for both bilayer (YIG/SmGG) and tri-layer (SmGG/YIG/SmGG) structural films with YIG layer thicknesses up to 20 nm and 40 nm, respectively
TL;DR: In this article, the authors used pulsed laser deposition (PLD) to produce crystalline hydroxyapatite (HAP) coatings at room temperature onto silicon substrates.
Abstract: Nd:YAG (532 nm) pulsed laser deposition (PLD) has been used to produce crystalline hydroxyapatite (HAP) coatings at room temperature onto silicon substrates. The PLD HAP coatings were homogeneous (100.4 nm RMS roughness) and consisted of micrometric particles (> 10 μm) coalesced over a nanometric dense layer. The deposition parameters of 532 nm laser, 30 J/cm2 fluence, 10− 4 Pa vacuum environment and room temperature are capable of coating any surface with crystalline HAP without requiring heat treatment. It was confirmed by Synchrotron Radiation Grazing Angle X-ray Diffraction (GAXRD) patterns that the nanocrystalline component present in the coatings was reduced and did not hide peaks of decomposition to other calcium phosphate (CaP) phases when in situ heat treatments of 200 °C and 800 °C were performed. The use of dense and stoichiometric HAP targets that could withstand the high-fluence laser allowed producing 150 nm crystalline HAP coatings in only 5 min of deposition time, although 532 nm laser wavelength is outside the absorption range of the HAP. This contribution opens the perspective to produce controlled PLD HAP coating over thermally sensitive substrates with reduced processing time for large-scale production for biomedical applications. As a demonstration, HAP coating was deposited and characterized on thermal sensitive bioabsorbable polylactide (PLA) surfaces.
TL;DR: In this article, a two-step spin-coating method was used to reduce the undesired hysteresis and indispensable high temperature process in perovskite-phenyl-C61-butyric acid methyl ester solar cells.
TL;DR: LiTa-doped Li7La3Zr2O12 (LLZO12) thin films were reported in this article, where the authors investigated the impact of laser fluence, deposition temperature, and postdeposition annealing on the structural, compositional, and transport properties of the film.
TL;DR: Taking advantage of this unique structure, a high saturation magnetization of ∼1375 emu cm-3 in the Co-BaZrO3 nanocomposites has been achieved and further confirmed by Lorentz microscopy imaging in TEM.
Abstract: A simple one-step pulsed laser deposition (PLD) method has been applied to grow self-assembled metal-oxide nanocomposite thin films. The as-deposited Co-BaZrO3 films show high epitaxial quality with ultra-fine vertically aligned Co nanopillars (diameter <5 nm) embedded in a BZO matrix. The diameter of the nanopillars can be further tuned by varying the deposition frequency. The metal and oxide phases grow separately without inter-diffusion or mixing. Taking advantage of this unique structure, a high saturation magnetization of ∼1375 emu cm-3 in the Co-BaZrO3 nanocomposites has been achieved and further confirmed by Lorentz microscopy imaging in TEM. Furthermore, the coercivity values of this nanocomposite thin films range from 600 Oe (20 Hz) to 1020 Oe (2 Hz), which makes the nanocomposite an ideal candidate for high-density perpendicular recording media.
TL;DR: In this paper, a comparative study of Pulsed Laser Deposition (PLD) based Tin Oxide (SnO 2 ) thin films deposited at various substrate deposition temperature (Ts) has been performed.
TL;DR: Initial results indicate similar improvements in film quality and magnetic properties due to the elimination of APBs in other members of the spinel ferrite family, such as Fe3 O4 and CoFe2 O4 , which have similar crystallographic structure and lattice constants as NiFe 2 O4.
Abstract: Spinel ferrite NiFe2 O4 thin films have been grown on three isostructural substrates, MgAl2 O4 , MgGa2 O4 , and CoGa2 O4 using pulsed laser deposition. These substrates have lattice mismatches of 3.1%, 0.8%, and 0.2%, respectively, with NiFe2 O4 . As expected, the films grown on MgAl2 O4 substrate show the presence of the antiphase boundary defects. However, no antiphase boundaries (APBs) are observed for films grown on near-lattice-matched substrates MgGa2 O4 and CoGa2 O4 . This demonstrates that by using isostructural and lattice-matched substrates, the formation of APBs can be avoided in NiFe2 O4 thin films. Consequently, static and dynamic magnetic properties comparable with the bulk can be realized. Initial results indicate similar improvements in film quality and magnetic properties due to the elimination of APBs in other members of the spinel ferrite family, such as Fe3 O4 and CoFe2 O4 , which have similar crystallographic structure and lattice constants as NiFe2 O4 .
TL;DR: In this article, the authors demonstrate successful wafer scale integration of graphene-related materials by a pulsed laser deposition technique, and controlled conversion of p to n-type 2D rGO using a nanosecond ArF excimer laser.
Abstract: Physical properties of reduced graphene oxide (rGO) are strongly dependent on the ratio of sp2 to sp3 hybridized carbon atoms and the presence of different functional groups in its structural framework. This research for the very first time illustrates successful wafer scale integration of graphene-related materials by a pulsed laser deposition technique, and controlled conversion of p to n-type 2D rGO by pulsed laser annealing using a nanosecond ArF excimer laser. Reduced graphene oxide is grown onto c-sapphire by employing pulsed laser deposition in a laser MBE chamber and is intrinsically p-type in nature. Subsequent laser annealing converts p into n-type rGO. The XRD, SEM, and Raman spectroscopy indicate the presence of large-area rGO onto c-sapphire having Raman-active vibrational modes: D, G, and 2D. High-resolution SEM and AFM reveal the morphology due to interfacial instability and formation of n-type rGO. Temperature-dependent resistance data of rGO thin films follow the Efros-Shklovskii variable...
TL;DR: In this article, the synthesis of simple and Ti doped hydroxyapatite thin films of biological origin was reported, and detailed physical, chemical, mechanical and biological investigations were performed.
TL;DR: In this article, the influence of the Ti doping level on the photoelectrochemical properties of thin-film (∼50-nm) hematite photoanodes was examined.
Abstract: Doping with Ti enhances the electron conductivity and photoelectrochemical properties in hematite (α-Fe2O3) photoanodes with respect to those of undoped hematite photoanodes. However, the optimal doping level is unknown. This work examined the influence of the Ti doping level on the photoelectrochemical properties of thin-film (∼50-nm) hematite photoanodes. The films were deposited by pulsed laser deposition (PLD) on glass substrates coated with transparent electrodes (fluorinated tin oxide, FTO) from Ti-doped Fe2O3 targets with different Ti concentrations: 0 (undoped), 0.25, 0.8, 1, and 7 cation %. The film thicknesses, morphologies, microstructures, and optical properties were nearly the same for all of the photoanodes, thereby enabling systematic comparison of the effect of the doping level without spurious side effects related to morphological variations. The photoelectrochemical performances of all of the Ti-doped photoanodes were considerably higher than that of the undoped photoanode. Among the dop...
TL;DR: The results demonstrate that the Ag-doped DLC films are potentially useful biomaterials having both good mechanical properties and antimicrobial characteristics.
TL;DR: The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide at 230 °C was as high as 3.0 mA/cm2 at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported Bi VO4 films grown by physical vapor deposition (PVD) methods.
Abstract: We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm2 at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our B...
TL;DR: In this article, structural, optical, temperature and frequency dependent dielectric, and energy storage properties of pulsed laser deposited (100) highly textured BaZrxTi1−xO3 (x = 0.3, 0.4, and 0.5) relaxor ferroelectric thin films on La0.7Sr0.3MnO3/MgO substrates were reported.
Abstract: We report structural, optical, temperature and frequency dependent dielectric, and energy storage properties of pulsed laser deposited (100) highly textured BaZrxTi1−xO3 (x = 0.3, 0.4, and 0.5) relaxor ferroelectric thin films on La0.7Sr0.3MnO3/MgO substrates which make them potential lead-free capacitive energy storage materials for scalable electronic devices. A high dielectric constant of ∼1400–3500 and a low dielectric loss of <0.025 were achieved at 10 kHz for all three compositions at ambient conditions. Ultrahigh stored and recoverable electrostatic energy densities as high as 214 ± 1 and 156 ± 1 J/cm3, respectively, were demonstrated at a sustained high electric field of ∼3 MV/cm with an efficiency of 72.8 ± 0.6% in an optimum 30% Zr substituted BaTiO3 composition.
TL;DR: In this article, the CoO-Co nanocomposite films were successfully deposited at room temperature by pulsed laser deposition as an anode material for lithium-ion batteries.
TL;DR: This work provides good guidance for the design and fabrication of solar-energy-related devices employing NiO electrodes and plasmonic Au NIs and predicts that the plasmoelectric potential effect is considered to be a good explanation of the photocurrent enhancement at the off-resonance region.
Abstract: Plasmonics is a highly promising approach to enhancing the light-harvesting properties of hybrid organic/inorganic perovskite solar cells. In the present work, our cells have a p–i–n inverted planar structure. An ultrathin NiO film with two different thicknesses of 5 and 10 nm prepared by a pulsed laser deposition process on an ITO substrate with a faceted and furrowed surface enabled the formation of a continuous and compact layer of well-crystallized CH3NH3PbI3via an anti-solvent chlorobenzene process. The coverage mechanism of the NiO film on the ITO was clearly demonstrated through the J–V and external quantum efficiency (EQE) curves. Moreover, the results demonstrated that the gold nanoislands (Au NIs) increased the power conversion efficiency to 5.1%, almost double that of the samples without Au NIs. This result is due to the excitation of surface plasmons, which is characterized by strong scattering and enhancement of the electric field in the vicinity of the Au NIs loaded at the interface between the NiO and perovskite films. Additionally, we observed an enhancement of the EQE at wavelengths shorter than the plasmon resonance peak. In the current state, we speculate that the plasmoelectric potential effect is considered to be a good explanation of the photocurrent enhancement at the off-resonance region. Our work provides good guidance for the design and fabrication of solar-energy-related devices employing NiO electrodes and plasmonic Au NIs.
TL;DR: In this article, the epitaxial growth of Bi2Se3 topological insulator thin films by Pulsed Laser Deposition (PLD) is reported, which shows that the topological surface state can be obtained in PLD-grown Bi2O3 thin films.
Abstract: We report on epitaxial growth of Bi2Se3 topological insulator thin films by Pulsed Laser Deposition (PLD). X-ray diffraction investigation confirms that Bi2Se3 with a single (001)-orientation can be obtained on several substrates in a narrow (i.e., 20 °C) range of deposition temperatures and at high deposition pressure (i.e., 0.1 mbar). However, only films grown on (001)-Al2O3 substrates show an almost-unique in-plane orientation. In-situ spin-resolved angular resolved photoemission spectroscopy experiments, performed at the NFFA-APE facility of IOM-CNR and Elettra (Trieste), show a single Dirac cone with the Dirac point at E B ∼ 0.38 eV located in the center of the Brillouin zone and the spin polarization of the topological surface states. These results demonstrate that the topological surface state can be obtained in PLD-grown Bi2Se3 thin films.