Combination Of Pulsed Laser Deposition Research Articles

Combinatorial preparation and infrared screening of hydrogen sorbing metal alloys

We introduce the use of thin-film combinatorial methods to synthesize Mg-based hydrogen storage alloys and demonstrate the use of spatially resolved infrared imaging as a high throughput hydrogen storage candidate screening technique. Using a combination of pulsed laser deposition and magnetron sputtering, multicompositional samples were produced for hydrogen sorption studies. Analysis is presented of a sample that consists of 16 separate Mg–Ni–Fe ternary pads and 32 Mg–Ni or Mg–Fe binary pads. Hydrogen sorption related emissivity changes observed indicate a substantial decrease in hydriding temperatures, which sensitively depends on composition.

Fabrication of a micro-scale, indium-tin-oxide thin film strain-sensor by pulsed laser deposition and focused ion beam machining

Abstract A thin film strain-sensor having an active sensing area of 20 mm ×100 mm has been developed using a combination of pulsed laser deposition (PLD) and focused ion beam (FIB) machining to net shape. Sensors were made of indium-tin-oxide (ITO) thin films in the range 100–246 nm thick. Strain sensitivities of large-scale (smallest dimension=0.8 mm), small-scale (smallest dimension=0.25 mm) and FIB machined gages (smallest dimension=20 μm) are reported. Large-scale devices were deposited in a background oxygen pressure in the range 28–50 mTorr, while small-scale and FIB machined gages were deposited in 50 mTorr of oxygen, the largest achievable pressure in our system, which also yielded the largest strain sensitivities. Active strain-sensors were produced with gage factors ranging from −0.3 to −8.7 and showed a linear room temperature response with minimal hysteresis. The effects of imaging and machining with the FIB as well as the effects of an SiO 2 encapsulation layer on the electrical properties of the gages are reported.

Novel route for the epitaxial growth of (SrBa)Nb2O6 thick films by the sol-gel method using a self-template layer

A novel sol-gel processing method has been developed to fabricate epitaxial (SrBa)Nb2O6 (SBN) thin films on MgO substrates. It involves the introduction of a SBN self-template layer on MgO by pulsed laser deposition (PLD). Effects of the SBN self-template layer on the structural and morphological properties of the sol-gel-derived SBN films were investigated. Compared to the sol-gel-derived SBN films without a self-template layer, our new technique produces SBN films of excellent epitaxy and more dense grains with uniform distribution. This can be explained by the self-template-layer-induced homoepitaxial growth. The innovative processing method with combination of PLD and sol-gel is a promising technique in preparing high-quality, thick epitaxial SBN films for electro-optics device applications.

TiN growth on Si by hybrid radical beam PLD

High-quality (good crystallinity and stoichiometry) titanium nitride (TiN) thin films were grown on Si(100) substrates by pulsed laser deposition (PLD) using a high-purity titanium target (99.99%) and nitrogen radical beam. The crystallinity, chemical composition, and depth profiles of the grown films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS), respectively. The XRD pattern indicated that the preferred growth of TiN(200) with an orientation parallel to the Si(100) direction was obtained and the nitrogen radical drastically improved crystallinity compared with that grown in ambient nitrogen gas. RBS spectra indicated that the combination of PLD and the nitrogen radical beam suppressed silicidation at the interface between the Si substrate and TiN thin film during growth. The XPS analysis revealed that this method achieved the synthesis of stoichiometric TiN films.

Magnetic field and temperature dependence of critical current densities in multilayer YBa2Cu3O7−δ films

In order to build high-temperature superconductor (HTS) multichip modules (MCMs), it is necessary to grow several epitaxial layers of YBCO that are separated by thick dielectric layers without seriously affecting the quality of the YBCO layers. In this work, we have successfully fabricated YBCO/YSZ/SiO2/YSZ/YBCO structures on single-crystal LaAlO3 substrates using a combination of pulsed laser deposition for the YBCO layers and ion-beam-assisted rf sputtering to obtain biaxially aligned YSZ intermediate layers. The bottom YBCO layer had a Tc∼89 K, Jc∼7.2×105 A/cm2 at 77 K, whereas the top YBCO layer had a Tc∼86 K, Jc∼6×105 A/cm2 at 77 K. The magnetic field and temperature dependence of Jc for the YBCO films in the multilayer have been obtained. The results for each of the YBCO layers within the YBCO/YSZ/SiO2/YSZ/YBCO structure are quite similar to those for a good quality single-layer YBCO film.

Ferroelectric PbZr0.2Ti0.8O3 thin films on epitaxial Y-Ba-Cu-O

Abstract Using a combination of pulsed laser deposition and sol-gel processing, we have fabricated epitaxial PbZr0.2Ti0.8O3/YBa2Cu3O7-x heterostructures on single crystalline [001] LaAlO3. Rutherford back-scattering studies show the composition to be the same as the nominal starting composition. Transmission electron microscopy shows the existence of a randomly oriented polycrystalline microstructure in the PZT layer with a grain size of about 500–1000A. Microscopic pores were also observed in the PZT layer. The PZT film exhibits ferroelectric hysteresis with a saturation polarization of 22–25μC/cm2 (at 7.5V, 1kHz), a remanence of 5–6μC/cm2 and a coercive field of about 40kV/cm.