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Triboluminescence was measured in alkaline earth aluminate polycrystals doped with Dy3+.

We studied energy transfer from AlN to doped Gd3+ ions as a function of the post-thermal annealing temperature. Gd-doped AlN thin films were deposited on fused-silica substrates using a reactive radio-frequency magnetron sputtering technique. The film is a c-axis oriented polycrystal. The intraorbital electron transition in Gd3+ showed an atomically sharp luminescence at 3.9 eV (318nm). The photoluminescence (PL) excitation spectrum exhibited a resonant peak, indicating efficient energy transfer from the host AlN crystal to Gd3+ ions. The PL intensity increases approximately ten times by thermal annealing. The PL decay lifetime becomes long with annealing, and mid-gap luminescence relating to the crystal defects in AlN was also found to be reduced by annealing. These results suggest that energy dissipation of excited carriers in AlN was suppressed by annealing, and the efficiency of energy transfer into Gd3+ was improved. [ABSTRACT FROM AUTHOR]

We studied the deep-ultraviolet emission properties of Al0.999Gd0.001 N thin films pumped by an electron beam. The Al0.999Gd0.001 N thin films were grown on fused silica substrates using an ultra-pure reactive sputtering technique. The intra-orbital electron transition of the Gd3+ ions in Al0.999Gd0.001 N showed an extremely narrow luminescence line at 318 nm. We fabricated field-emission devices using an Al0.999Gd0.001 N phosphor thin film and analyzed the dependence of the device characteristics on the injected current and acceleration voltage. The maximum output power was 1.0 mW/cm2. The excitation cross section was of the order of 10-13 cm2 and was found to depend on the acceleration voltage. These results indicate that injected high-energy electrons multiply excite Gd3+ ion. [ABSTRACT FROM AUTHOR]

We investigated the narrowband ultraviolet emission properties of Al0.94Gd0.06N phosphor thin films pumped by an electron beam. An extremely narrow luminescence line, which was less than 1 nm from the intra-orbital f-f transition in Gd3+ ions, was confirmed at 318 nm. The corresponding emission efficiency was improved by decreasing the growth temperature. The extended X-ray absorption fine structure analysis of the local atomic structure revealed that a low-temperature growth led to the formation of a uniform atomic configuration around Gd, which was found to play a key role in improving the luminescence intensity of the films. [ABSTRACT FROM AUTHOR]

The relation between electrical and structural properties of indium tin oxide (ITO) films prepared by pulsed laser deposition with and without in situ laser irradiation is examined. The residual stresses of the films were estimated from x-ray diffraction patterns measured by grazing-incidence asymmetric Bragg and grazing-incidence x-ray diffraction geometries. For the films prepared without in situ irradiation, the residual stress depended on oxygen pressure (P[sub O[sub 2]]) during deposition and had minimum around P[sub O[sub 2]] of 1.3 Pa, which coincided with the optimum P[sub O[sub 2]] for growing the lowest resistivity films. The resistivity was only slightly improved with an increase of substrate temperature (T[sub s]) because a large residual stress was introduced. In contrast, the ITO films prepared with in situ laser irradiation showed very low resistivity (ρ<10[sup -4] Ω cm) which can be attributed to the high crystallinity and low residual stress. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Indium-tin-oxide film (ITO) was fabricated on a (100) surface of an yttria-stabilized zirconia (YSZ) single crystal by pulsed laser deposition. The ITO film was characterized by atomic force microscopy and X-ray diffraction measurements. ITO grew heteroepitaxially on the YSZ substrate. The ITO film surface was extremely flat and roughness in height was less than 1 nm. Two organic dyes, copper phthalocyanine and vanadyltetraphenylporphyrin, were vacuum-deposited on the ITO substrate. Their molecular orientations in thin film were investigated by transmission electron microscopy and electron diffraction analysis. [ABSTRACT FROM AUTHOR]