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Abstract: We here report the structural and optical studies of Zn1−x−y Be x Mg y O (0≤ x ≤0.15; 0≤ y ≤0.20) powders and thin films. From the Rietveld refinement of the powder X-ray diffraction (XRD) patterns it was revealed that the value of ‘a’ lattice parameter remains almost unchanged whereas ‘c’ parameter reduces with Be and Mg co-doping in ZnO. The Zn-O bond length also decreases in co-doped samples. Raman studies of the pure ZnO powder showed all the characteristic peaks of the wurtzite hexagonal structure and with (Be, Mg) co-doping new modes appeared which can be attributed to arise as a result of substitution. The XRD of the films prepared from the powders using pulsed laser deposition (PLD) technique exhibited the preferential orientation and with increase in co-doping the (0002) peak also shifts to higher 2θ values suggesting the incorporation of Be/Mg at the Zn-site. From the UV–visible optical transmittance measurement it was noticed that the band gap of the pristine ZnO film is 3.3eV which enhanced up to 4.51eV for Zn0.7Be0.1Mg0.2O film which lies in the solar blind region and is very useful in the realization of deep UV detectors. [ABSTRACT FROM AUTHOR]

Abstract Varying the substrate temperature changes structural and magnetic properties of spinel ferrite Ni 0.65 Zn 0.35 Fe 2 O 4 (NZFO) thin films. X-ray diffraction of films grown at different temperature display only (004) reflections, without any secondary peaks, showing growth orientation along the c-axis. We find an increase in crystalline quality of these thin films with the rise of substrate temperature. The surface topography of thin films grown at different growth temperatures reveal that these films are smooth with low roughness; however, the thin films grown at 800 °C exhibit lowest average and root mean square (rms) roughness among all thin films. We find iron and nickel to be more oxidized (greater Fe3+ and Ni3+ content) in films grown and annealed at 700 °C and 800 °C, compared to those films grown at lower temperatures. The magnetic moment is observed to increase with an increase of substrate temperature and all thin films possess high saturation magnetization and low coercive field at room temperature. Films grown at 800 °C exhibit a ferrimagnetic–paramagnetic phase transition well above room temperature. The observed large magnetizations with soft magnetic behavior in NZFO thin films above room temperature suggest potential applications in memory, spintronics, and multifunctional devices. Highlights • Highly c-axis oriented NZFO thin films were grown by PLD technique. • Varying the substrate temperature changes structural and magnetic properties. • All thin films exhibit high Ms, low Mr and low Hc at room temperature. • The M s is found to be increased with increase of substrate temperature. • Thin films grown at 800 °C exhibit a ferrimagnetic Tc ∼716 (±10) K. [ABSTRACT FROM AUTHOR]

This article presents the effect of lead-borosilicate glass (65PbO 20B 2 O 3 15SiO 2 , mol%) (PBS) addition on the structure, microstructure, dielectric, ferroelectric and energy storage properties of Ba 0.9995 La 0.0005 TiO 3 (BLT) ceramics system has been systematically investigated. XRD analysis revealed the tetragonal (T) phase at room temperature. Addition of PBS glass results in decrease in ferroelectricity and improved breakdown properties. High maximum polarization (P s ∼21.53 μC/cm 2 ) and remnant polarization values (2P r ∼8.75 μC/cm 2 ) were obtained from ferroelectric (P-E) hysteresis loops for the BLT ceramics. Two dielectric anomalies at 420 K and 600 K were observed due to the phase transformation. The glass-ceramics heat treated at 900 °C for 3 h was found to possess optimal properties with breakdown strength of >300 kV/cm and energy storage density of 0.564 J/cm 3 , which is a promising glass-ceramic ferroelectric capacitor material for high energy storage density dielectrics. [ABSTRACT FROM AUTHOR]

We have investigated optical and band alignment properties of pulsed laser deposited amorphous thin films of bismuth based monoclinic pyrochlore Bi 2 Zn 2/3− x /3 Nb 4/3−2 x /3 Zr x O 7 (Zr–BZN) where x = 0.4 on quartz and silicon substrates, respectively. The optical parameters, such as complex refractive index ( n − jk ), energy bandgap ( E g ), complex dielectric function ( ε ′ - j ε ″ ), and complex conductivity ( σ ′ - j σ ″ ) and associated dispersion parameters were estimated from the UV–Visible transmission spectra. The analysis of refractive index dispersion confirmed the Wemple–DiDomenico single-effective-oscillator model for the direct inter-band transition. The valence band of Zr–BZN is found to be ∼0.1 eV above that of silicon. The numerical values for conduction band offset Δ E C on silicon and optical bandgap E g were estimated to be ∼2.46 eV and ∼3.46 eV, respectively for Zr–BZN samples. We determined a complete electron band offset dominated type II staggered band lineup of this high- k dielectric/semiconductor heterostructure, where a straight forward spatial confinement of electrons and holes is facilitated. These important results can play critical role and provide key insight for the practical applications of Zr–BZN material, especially in CMOS (complementary metal–oxide–semiconductor) logic and memory devices. [ABSTRACT FROM AUTHOR]

In this work, we report a novel carbon based TiO 2 nanocomposite electron injection layer (photoanode) toward the improved performance of DSSCs. Graphitic carbon nanospheres (GCNSs) were synthesized by a unique acidic treatment of multi-wall carbon nanotubes. GCNS–TiO 2 nanocomposites with different concentrations of GCNSs (ranging from 5 to 20 μL) were prepared to use as photoanodes in DSSCs. Structural and morphological properties of GCNS–TiO 2 nanocomposites were analyzed by Raman spectroscopy and ultra-high resolution transmission electron microscopy techniques, respectively. A systematic increment in the short circuit current density ( J SC ) and open circuit voltage ( V OC ) of DSSC was observed by increasing GCNS concentration up to an optimal value, possibly due to the combined effect of slight rise in quasi-Fermi level and higher carrier transport rate in the resultant composite. Thus, a significant enhancement of ∼47% in the efficiency of DSSC containing GCNS–TiO 2 photoanode was observed as compare to DSSC with pure TiO 2 photoanode. [ABSTRACT FROM AUTHOR]

Highlights: [•] High quality thin film of multiferroic BiFeO3 on SrRuO3 is grown by RF Sputtering. [•] The Pt/BFO/SRO structure showed diode like behavior through I–V measurement. [•] Appreciable VOC and JSC were observed with illumination of white light. [•] The photoresponse at zero bias of BFO film showed rapid increase in photocurrent. [•] Application of BFO film for photosensitive capacitor is demonstrated. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have synthesized calcium substituted BaTiO3 ceramics by solid state route. [•] We have studied P–E loops with ferroelectric and antiferroelectric like double hysteresis behavior for naturally aged BCT. [•] Moderate energy densities with good energy storage efficiency (∼61%) were observed. [ABSTRACT FROM AUTHOR]

Highlights: [•] ZnO–graphene nanocomposite has been synthesized. [•] ZnO nanocrystals are formed on the surface of graphene. [•] ZnO–graphene based dye sensitized solar cell shows enhanced photovoltaic performance. [ABSTRACT FROM AUTHOR]

Critical structural variation and dielectric properties were investigated in Lanthanum and Gadolinium co-substituted bismuth ferrite (Bi 0.9 La 0.1 Fe 1-x Gd x O 3 (x = 0.01, 0.03, 0.05, 0.07, 0.1, and 0.15). Conventional solid state reaction technique was used to synthesize ceramic samples. To investigate the influence of co-substitution on the phase formation and crystal structure, X-ray diffraction method (XRD), Scanning electron microscopy (SEM) and Raman spectroscopy were utilized. Probing the structural properties by changing Gd ratio was carried out to ensure single phase of rhombohedral R 3 c structure. Hence, the exploration of dielectric properties of single phase modified BiFeO 3 (BFO) ceramic was executed by room temperature capacitance and loss tangent measurements. It was found that by substitution of 10 mol% La for Bi and up to 5 mol% Gd for Bi, perovskite structure of rhombohedral symmetry and R 3 c space group were formed. This possessed enhanced magnetization and reduced dielectric loss compared to pure BFO. Image 1 • Critical structural variation on La and Gd co-substituted BiFeO 3. • Substitution of 10 mol% La for Bi and up to 5 mol% Gd for Bi. • Formation of perovskite structure of rhombohedral symmetry and R 3 c space group. • The exploration of dielectric properties of single phase Bi 0.9 La 0.1 Fe 1-x Gd x O 3 ceramics. • Success of enhanced magnetization and reduced dielectric loss. [ABSTRACT FROM AUTHOR]