Europium doped yttrium oxide (Eu:Y2O3) phosphor thin films were grown using a pulsed laser deposition (PLD) technique at varying growth conditions. The structural characterization carried out on a series of Eu:Y2O3 films grown on (100) silicon at substrate temperatures in the range of 250–600 °C and oxygen pressure in the range of 10−5 Torr to 200 mTorr indicated that films were preferentially (111) oriented. Measurements of photoluminescence and cathodoluminescence properties of laser deposited Eu:Y2O3 thin films and powder used for laser target showed that the best in situ grown films were ∼10%–22% as bright as Eu:Y2O3 powder. A postdeposition annealing treatment of Eu:Y2O3 films led to further improvements in their brightness (up to ∼70% with respect to Eu:Y2O3 powder), with cluster sizes of <400 nm.

Luminescence of pulsed laser deposited Eu doped yttrium oxide films

Thin-film Y3−xAl5O12:Tbx3+ (YAG:Tb) phosphor derived from a sol-gel chemistry is analyzed by x-ray diffraction, scanning electron microscopy, photoluminescence (PL) and cathodoluminescence (CL). The metal alkoxides organic precursors were chosen as the starting materials to form the sol-gel. This liquid sol-gel was spin coated on sapphire and silicon substrates to form the uniform thin films, then crystallized by annealing. The PL intensity of the crystallized film at 545 nm green emission was 15 times higher than that of the as-coated noncrystalline film. CL measurements show that luminance and efficiency are comparable to the films deposited by other techniques.

Alkoxy sol-gel derived Y3−xAl5O12:Tbx thin films as efficient cathodoluminescent phosphors

Standard free energy of formation of YFeO3, Y3Fe5O12, and a new compound YFe2O4 in the FeFe2O3Y2O3 system at 1200°C

The in situ excimer‐laser deposition process is demonstrated, for the first time, to be an effective technique for producing superconducting films on both sides of substrate wafers of up to 5 cm in diameter. By exploiting the directed nature of the laser produced plume and controlling its off‐axis composition, thickness and stoichiometric variations of less than ±5% have been obtained over the entire surface. Coatings on 5‐cm‐diam LaAlO3 substrates have uniform transition temperatures of ≥ (R18)90 K on both sides, with a critical current density at 77 K and zero field of 2.5×106 A/cm2. The 10 GHz surface resistance for samples cut from a 5 cm wafer is 40–60 μΩ at 4 K.

Large‐area, two‐sided superconducting YBa2Cu3O7−x films deposited by pulsed laser deposition

Compositions in the system Fe2O3-FeO-BaO in the vicinity of the compound BaFe12O19 were studied at temperatures from 1300° to 1550°C and oxygen pressures from 10−2 to 102 atm. Equilibrium relations involving several barium ferrous ferrites are described. Barium ferrite can be crystallized congruently from the melt at 40 atm oxygen pressure and 15400°C.

Thermal Stability of Barium Ferrite (BaFe12O19)

Measurements were made of temperature and ternary composition for coexisting liquid and crystalline phases on the air isobar in the system Fe2O3-Fe3O4-YFeO3 with particular regard to the stability range and compositional limits of yttrium iron garnet. Phase equilibrium relations were determined by conventional quenching techniques combined with measurements of loss in weight at the reaction temperature to locate true ternary compositions. The intersection of the air isobar with the ternary univariant boundary curve for coexisting magnetite, garnet, and liquid phases results in a eutectic-type situation at the composition Y0.27Fe1.73 O2.87 and 1469°± 2°C. A similar intersection of the isobar with the boundary curve for coexisting garnet, orthoferrite, and liquid phases gives rise to a peritectic-type reaction at 1555° 3°C. and Y0.44Fe1.56 O2.89 The yttrium iron garnet crystallizing from liquids within these temperature and composition limits contains up to 0.5 mole % iron oxide in excess of the stoichiometric formula in terms of the starting composition 37.5 mole % Y2O3, 62.5 mole % Fe2O3. At 1470° C. the garnet phase in equilibrium with oxide liquid contains 2 mole % FeO in solid solution. The small solubility of excess of iron oxide and partial reduction of the garnet phase in air are unavoidable during equilibrium growth from the melt.

Phase Relations in the System Fe2O3–Fe3O4–YFeO3 in Air

Influence of Oxygen Pressure on Incongruent Melting Temperature of Yttrium Iron Garnet

High luminance (brightness) thin-film phosphor materials have potential use in a variety of applications including heads-up, helmet-mounted, and electroluminescent displays, as well as in emerging flat-panel displays based on field emitter technology. Phosphor materials in thin film form offer several advantages over conventional powder phosphor screens. Since the film is nearly fully dense and in intimate contact with the underlying substrate, thin film phosphors transfer heat to the face plate much quicker than conventional, more porous, powder phosphor materials. This allows thin film phosphor screens to be driven at higher power levels, and therefore produce higher luminance, assuming the efficiency of the powder and film are the same. Fully dense phosphor films have smaller surface area, and will outgas less than conventional powder phosphor materials. Thin film phosphors have smaller grain sizes than conventional powder phosphor materials which will provide for smaller spot size, and thus, higher resolution. Furthermore, in applications such as field-emitter displays, powder phosphor particles can be physically dislodged from the screen due to the high electric fields produced by the large potential difference between the anode screen and gate electrode (or cathode), or dislodged by arcing which may occur if a powder particle protrudes significantly above the screen surface. Dislodged particles or damage produced by arcing could degrade display performance. Dense, thin-film phosphor materials which are well adhered to transparent substrates will provide much smoother surface morphologies, and should be able to withstand significantly higher electric field strength without arcing or screen degradation due to the dislocation of particles.

Laser-Deposition Of High Luminance Thin Film Phosphors

From available single-crystal data on YIG:Ga and YIG :Ca-V-In, a comparison has been made of anisotropy line broadening in each series for compositions with equivalent 4\piM_{s} and T c . The results indicate the latter materials have smaller anisotropies and should therefore have inherently lower magnetic loss when comparing ceramics with near perfect microstructures, i.e., where porosity line broadening is negligible.

Microwave loss in low-magnetization polycrystalline garnets: A comparison of Ga and CA-V-In-substituted YIG

1 3 1 Spring Street, Lexington, MA 02173ABSTRACTDue to its short wavelength and high peak power, the excimer laser has become the de facto choice forPulsed Laser Deposition (PLD) of ceramic superconductors as well as other complex chemical compounds.This paper will describe a unique excimer-based laser deposition system which is capable of producing thinfilms of a variety of oxide compounds or other materials over large areas (up to 46 cm2). Well over a dozenchemical compounds have been deposited with this system for a wide variety of electronic applications.Also, the PLD technique has been adapted to grow thin films on the internal surface of cored cylindricalsubstrates in order to form resonant microwave cavity structures. The uniformity, morphology, andelectrical properties of films grown on both planar and cylindrical substrates will be discussed.2. INTRODUCTIONPLD has recently become a routine research technique for the development of thin films for a variety ofcomplex chemical compounds, and most notably high temperature superconducting (HTS) oxides' '

H. J. Van Hook

Papers

Phase Relations in the System Fe2O3–Fe3O4–YFeO3 in Air

Influence of Oxygen Pressure on Incongruent Melting Temperature of Yttrium Iron Garnet

Laser-Deposition Of High Luminance Thin Film Phosphors

Microwave loss in low-magnetization polycrystalline garnets: A comparison of Ga and CA-V-In-substituted YIG

Pulsed-laser deposition of oxides over large areas