Size Controlled CaF2Nanocubes and Their Dosimetric Properties Using Photoluminescence Technique

A new synthetic chemical coprecipitation route for the preparation of well-crystallized size controlled nano- and microcrystalline cubes of CaF2is reported. Crystalline cubes in the range of 2 μm–20 nm could be synthesized and their sizes were controlled by varying the solvent : cosolvent ratio. The as-synthesized CaF2nanocubes were characterized by different techniques. Photoluminescence (PL) emission spectrum of CaF2nanocrystalline powder showed strong emission band at 415 nm. Moreover, the effect of Eu as a dopant on the emission spectrum of CaF2was investigated. This dopant was found to get incorporated in its Eu2+and Eu3+forms. The as-produced nanocubes were exposed to UV irradiation and the corresponding PL emission was studied. Excellent results are obtained, where CaF2:Eu nanocubes were found to be highly sensitive and might be suitable for esteeming the doses of UV irradiation using the PL technique.

Synthesis and Fluorescence Properties of a New Eu(III) Complexes with β-Diketone Ligand

A novel β-diketone 4-[4-(Dibenzylamino) phenyl]-2,4-dioxobutanoic (DPD) and its corresponding Eu3+ complex with 1,10-phenanthroline were synthesized. The structure, thermal behaviour and fluorescence property of the complex was characterized by Fourier Transform Infrared (FT-IR), thermal gravimetric analysis (TGA) and fluorescence spectrophotometer. The fluorescence characterization shown that the addition of β-diketone and 1,10-phenanthroline enhance the fluorescence intensity of the complex. Eu3+ complex was considered to be a valuable organic light-emitting material with bright red fluorescence because of its strong emission band. Furthermore, the thermal stability characterizarion shows that the obtained rare earth β-diketone complexes have good thermostability.

Growth of β-Ga2O3 Nanoparticles Doped with Tin by Ni2+ Catalyzed Chemical Vapor Deposition

Sn-doped monoclinic β-Ga2O3 nanoparticles were successfully fabricated on Si (111) substrates with NiCl2 as a catalyst by chemical vapor deposition using metallic gallium and oxygen as sources. The composition, crystal structure, morphology, and optical properties were characterized by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectrophotometry (FTIR), and photoluminescence, respectively. The results demonstrate that the sample was monoclinic β-Ga2O3 nanoparticles with diameters approximately ranging from 200~300 nm. Well-defined prominent absorption bands located at 458 and 671 cm-1 in the FTIR spectra corresponded to Ga-O vibrations. The photoluminescence spectrum shows that the Ga2O3 nanoparticles have a broad and strong emission band ranging from 300 nm to 650 nm with four Gaussian bands centered at approximately 346 (UV), 416 (blue), 473 (dark blue), and 529 nm (green), which may be attributed to defects such as oxygen vacancies and galliumoxygen vacancy pairs. The growth mechanism of β-Ga2O3 nanoparticles is discussed in brief.

Low Reflectivity ErAlO Film on Si as Anti-Reflecting Coating in Solar Cells

Amorphous Al2O3 and Er2O3 alloyed films were deposited on Si(001) substrates by radio frequency magnetron sputtering technique. Ellipsometry measurements show that the weighted average reflectivity in the wavelength between 400 and 1000 nm for the ErAlO is 2.25%. Emission spectra exhibit a strong emission band around 410 nm and a series of emission band near 970 and 1019 nm. All the results indicate that ErAlO could be a promising material for Si solar cells.

Study on the Luminescence and Reflection Spectra of Al2O3 Doped Er2O3 Films on Si Substrates

Amorphous Al2O3 doped Er2O3 films were deposited on Si(001) substrates by radio frequency magnetron sputtering technique. Emission spectra exhibit a strong emission band around 410 nm and a series of emission band near 970, 980, 1018, 1042 and 1080nm. Ellipsometry measurements show that the refractive indexof the ErAlO films in the region of 400～1000 nm is between 1.76-1.83. The reflectivity of the ErAlO on Si is much smaller than that of clean Si and pure Er2O3 films. All the results indicate that ErAlO could be a promising material for Si solar cells.

Synthesis, Crystal Structure and Luminescence Properties of a Cyclometalated Ir(III) Complex of 3,4-Diphenylcinnoline

An iridium(III) complex, [(dpci-H)2Ir(dafo)](PF6) (dpci-H = deprotonated 3,4-diphenylcinnoline, dpci; dafo = 4,5-diazafluoren-9-one), was synthesized from the reaction of the iridium complex [Ir(dpci-H)2(Cl)]2 and dafo in methanol, and characterized by single-crystal X-ray diffraction along with FT-IR, UV/Vis, 1H NMR and mass spectroscopy. The luminescence properties and the decay of the cyclometalated iridium(III) complex were also investigated. Excitation at the absorption wavelength (469 nm) resulted in a strong emission band centered at 591 nm with a lifetime of 0.9 μs.

A SIMPLE XUV SOURCE AT 13.5 NM BASED ON ABLATIVE CAPILLARY DISCHARGE

A XUV source that produces a strong emission band at the wavelength of 13.5 nm with a FWHM of 0.6 nm and a duration of about 100 ns is described. In particular this wavelength has attracted the attention of many scientists working in the field by being a good candidate for the development of XUV lithography. The source was generated by using an ablative capillary discharge where the capillary was made of PVC (polyvinyl chloride). A remarkable burst of radiation at the above wavelength was recorded, the intensity of the radiation being higher by a factor of 10 in the spectral region of interest, as compared to usually used capillaries made of POM (polyacetal), or to recently developed capillary discharges in noble gases. Total XUV radiation energy of up to 50 mJ per pulse seems to be possible with such a device. Due to its simplicity, the described capillary discharge is a good candidate for a simple incoherent XUV source at 13.5 nm.

SIMS and Cl Characterization of Manganese-Doped Aluminum Nitride Films

ABSTRACTWe have recently carried out MOCVD experiments that showed for the first time the doping of AlN thin films with manganese. Films of AlN that were doped with less than 0.1% of manganese showed emission bands at 427 nm, 488 nm and 600 nm in accordance with previous published excitation and emission spectra of manganese incorporated in bulk A1N. A film with a higher percentage of manganese (1.7%) grown on top of a pure A1N layer (underlayer) showed weak emission at 601 nm. A portion of the underlayer not covered during growth of the overlayer has a very strong emission band at 408 nm and a weaker band at 605 nm. SIMS and EDX analyses of this film revealed both carbon and oxygen contamination as well as diffusion of manganese into the A1N underlayer. The band at 408 nm is associated with direct gap emission from oxygen contaminated A1N and the band at 605 nm is from manganese incorporated by diffusion into the A1N underlayer.

Luminescence Measurement of Fused Silica in the Presence of Excimer Laser Radiation

Exicimer laser induced luminsecence characteristics of type III fused silica was investigated. The luminescence characteristics in the ultraviolet wavelength region are strongly depending on the intensity of red luminescence at 650 nm. A sample without red luminescence shows a strong emission band at 280 nm. We found that the 280 nm band is corresponds to a absorption band at 225 nm. To clearfy the nature of the 280 nm band, we studied the difference of luminescence of samples which had been kept on heating under various atmosphares, i.e., N2, O2, He, H2, and air. By these results we suspect that the 280 nm band is related to hydrogen atom which are weakly bounded to the glass network.