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In situ external magnetic field was applied during the synthesis of FePt nanoparticles via a chemical solution method. FePt nanoparticle films were prepared on Si by a drop-coating method with and without a magnetic field. Annealing at 700 °C in reductive atmosphere was explored to obtain ferromagnetic FePt L1 phase. The effect of in situ-applied magnetic field on the structure, morphology, and magnetic properties of FePt nanoparticle films was characterized. It is found that the applied magnetic field during the chemical synthesis of FePt nanoparticles plays a key role in the crystallinity and magnetic property of FePt nanoparticle films. As-synthesized FePt nanoparticles under the magnetic field are monodispersed and can be self-assembled over a larger area by a dropping method. The applied magnetic field during the synthesis of FePt nanoparticles not only significantly improves the nanoparticles' c-axis preferred orientation but also benefits the phase transition of FePt nanoparticles from face-centered cubic to face-centered tetragonal structure during the annealing process. The FePt nanoparticle films derived under magnetic field also show some magnetic anisotropy. [ABSTRACT FROM AUTHOR]

Abstract: We report the characteristics of HfO2 films deposited on Ge substrates with and without La2O3 passivation at 250°C by atomic layer deposition (ALD) using La[N(SiMe3)2]3 and Hf[N(CH3)(C2H5)]4 as the precursors. The HfO2 is observed to form defective HfGeO x at its interface during 500°C postdeposition annealing. The insertion of an ultrathin La2O3 interfacial passivation layer effectively prevents the Ge outdiffusion and improves interfacial and electrical properties. Capacitance equivalent thickness (CET) of 1.35nm with leakage current density J A of 8.3×10−4 A/cm2 at V g =1V is achieved for the HfO2/La2O3 gate stacks on Ge substrates. [Copyright &y& Elsevier]

The authors have investigated the effect of 500 °C annealing for 60 s in N2 on interfacial and band alignment characteristics of HfO2/SiO2 gate stacks on n-type Ge substrates. X-ray photoelectron spectroscopy analyses reveal that the SiO2 interlayer can effectively suppress Ge outdiffusion during HfO2 growth and subsequent postdeposition annealing process. The electrical measurement shows that capacitance equivalent thickness of 1.75 nm and a leakage current density of 3.9 × 10-3 A/cm2 at gate bias of flatband voltage (Vfb) + 1 V was obtained for the annealed sample. The conduction band offsets at the HfO2/SiO2/Ge with and without annealing are found to be 2.22 and 2.07 eV, respectively. [ABSTRACT FROM AUTHOR]

Cu 2 ZnSn(S x Se 1− x ) 4 nanocrystals have been successfully synthesized by a novel two-step route involving a solvothermal reaction of Cu 2 ZnSnSe 4 and a sulfurization post-annealing. The Se 2− is gradually replaced by the S 2− to form the CZTSSe solid solutions with a tetragonal structure when increasing the sulfurization time. The A 1 Raman modes of CZTSSe display a typical two-mode behavior, revealing that S composition plays an important role on tuning the vibrating modes. The optical band gap becomes large gradually from 0.91 to 1.30 eV with increasing S content from 0 to 0.76. CZTSSe nanocrystals derived from this method can be used as low-cost absorber layer for photovoltaic applications. [ABSTRACT FROM AUTHOR]

Abstract: Gd2− x La x O3 high-k films were deposited on (100) Si substrates by low-pressure metal-organic chemical vapor deposition (MOCVD). The metal-organic precursors we used were Gd and La β-diketonates. The structure, band gap, composition and electrical properties of Gd2− x La x O3 films have been investigated. X-ray diffraction patterns show that as-deposited thick Gd2− x La x O3 films on Si have formed cubic phase of solid solution with (222) preferred orientation. The band gap of the Gd2− x La x O3 films can be calculated to be 5.78eV using a UV–vis–NIR spectrophotometer. X-ray photoelectron spectroscopy depth profile analyses reveal that there exists an interfacial layer of Gd–La–Si–O silicate and the La element is rich in interfacial layer. The equivalent oxide thickness (EOT) of 1.08nm has been obtained with the flatband voltage (V fb) of 1.0V and leakage current density (J A) of 3A/cm2 at V g = V fb +1V for Gd2− x La x O3 (x =1.29) films of 8nm physical thickness after 800°C post-annealing. [Copyright &y& Elsevier]