Volume 114, Issue 2, 14 July 2013
Index of content:
- SPECIAL TOPIC: Selected Papers from the International Symposium on Integrated Functionalities 2012, Hong Kong, June 17-21, 2012
Effect of Mn doping on structures and properties of chemical solution deposited lead zirconate titanate thick films with (100) preferential orientation114(2013); http://dx.doi.org/10.1063/1.4812226View Description Hide Description
Mn doped PbZr0.52Ti0.48O3 (PZT) thick films with highly (100) preferential orientation have been prepared by chemical solution deposition according to doping concentration of 0, 0.5, 1, 2, and 3 mol. %. The effect of Mn-doping on structures and electrical properties of PZT thick films has been investigated. With increasing Mn doping concentration, the dielectric constant first increases and then decreases. PZT film with 0.5 mol. % Mn doping has a maximum value of 2252 and a dielectric loss of 0.011 at 1 kHz. Mn doping below 3 mol. % could effectively reduce the leakage current density of PZT films. The mechanism of Mn doping on dielectric and ferroelectric properties of PZT thick films has been investigated and discussed.
114(2013); http://dx.doi.org/10.1063/1.4812227View Description Hide Description
In the present work, effects of annealing time on strain behavior, densification, and microstructure of 2 wt. % B2O3 doped Ba(Zr0.07Ti0.93)O3 ceramics were investigated. The ceramics were initially sintered at 1150 to 1275 °C for 2 h. After sintering, the densest ceramics (1250 °C ceramics) were selected for annealing at 1000 °C for 4-16 h. An increase in strain level and piezoelectric coefficient was observed after some annealing. High bipolar strain level of 0 .48% and high piezoelectric coefficients (d * 33) of 603 pm/V were obtained for the 8 h samples. Longer annealing times (>8 h) resulted in reduction of the strain level and piezoelectric value. The change in piezoelectric properties was correlated with the densification and microstructure of the studied samples.
114(2013); http://dx.doi.org/10.1063/1.4812219View Description Hide Description
Ag nanoparticle (NP) embedded BaTiO3 (BTO) thin films on SrRuO3-coated SrTiO3 (STO) substrates are prepared by the integrated nanocluster beam deposition and laser-molecular beam epitaxy. Enhanced resistive switching, up to an ON/OFF ration of 104, has been achieved at low switching voltage (less than 1 V) without a forming voltage. These characteristics make such nanocomposite film very promising for application of low voltage non-volatile random access memory. The enhanced resistive switching effect may be attributed to the charge storage effect of the Ag nanoparticles and easy formation of Ag filament inside the BTO film.
Thickness variation of electrophoretically deposited strontium titanate films for photoelectrochemical energy conversion114(2013); http://dx.doi.org/10.1063/1.4811817View Description Hide Description
Photoelectrochemical cells consisting of strontium titanate (SrTiO3) films on nickel substrates in potassium hydroxide electrolyte have been developed. SrTiO3 film thicknesses in the range of 1 μm–8 μm have been realized by electrophoretic deposition (EPD). The EPD process enables to produce such films in only 12 s with very high reproducibility. The samples have been studied with the focus on their photocurrents under illumination with different wavelengths. Samples with a film thickness of 5 μm show the best performance, because the trade-off between high absorption and low recombination is highest. Under 365 nm illumination, these samples show light to current efficiencies of 8% and external quantum efficiencies of 23.6%.
Linear electro-optic properties of relaxor-based ferroelectric 0.24Pb(In1/2Nb1/2)O3-(0.76 − x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals114(2013); http://dx.doi.org/10.1063/1.4811811View Description Hide Description
Linear electro-optic properties of 0.24Pb(In1/2 Nb 1/2)O3-(0.76 − x)Pb(Mg1/3 Nb 2/3)O3-xPbTiO3 single crystals, with compositions in the rhombohedral, morphotropic phase boundary (MPB) and tetragonal phases, have been investigated. Very large effective electro-optic coefficient (204 pm/V) was observed in a crystal with the MPB composition when it is poled along . The rhombohedral phase (x = 0.27 and 0.30) single crystals poled along  direction and tetragonal phase (x = 0.39) single crystal poled along  direction are in single domain, and their electro-optic coefficients ( = 76, 94, and 43 pm/V for the crystals with x = 0.27, 0.30, and 0.39, respectively) were found to be much higher than that of traditional electro-optic single crystal LiNbO3 ( = 19.9 pm/V). The electro-optic coefficients of the single crystal in the rhombohedral phase have excellent temperature stability in the experimental temperature range of 10–40 °C. The half-wave voltage was calculated to be much lower (less than 1000 V) than that of LiNbO3 single crystal (2800 V). These superior properties make the ternary relaxor-PT single crystals very promising for electro-optic modulation applications.
114(2013); http://dx.doi.org/10.1063/1.4811820View Description Hide Description
LiNbO3 (LN) ferroelectric films were deposited on the ZnO buffered AlGaN/GaN templates by pulse laser deposition technique. The microstructures of the buffer layers and LN films were characterized by reflective high energy electron diffraction, atomic force microscope, and X-ray diffraction, respectively. With the help of Cu/Si3N4 double-layer masks, LN/ZnO/AlGaN/GaN transistors were fabricated and the electrical properties were studied. Normally off characteristics were exhibited for the fabricated transistors with LN gate layers. Due to the modifications of the 5-nm-thick ZnO layer to the interface, the electrical properties of the transistor were enhanced greatly. The maximum transconductance increased from 27 to 46 mS/mm, and the maximum drain current increased from 97 to 204 mA/mm. The operation mechanisms of the devices were proposed by the numerical calculations of the electronic band structure and charge distribution.