Papers by Keyword: Rare Earth Doping

Abstract: This paper fabricates rare earth(RE) La, Ce and Pr doped GaN film by sol-gel method and uses X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL) to characterize and analyze their dimensions, morphology and optical properties. The results show that doped GaN film is hexagonal wurtzite structure and has good crystallinity. With the increasing of the Ce doping amounts, the particle size of GaN increases gradually. While augmenting the doping amounts of La or Ce can cause particle size to be smaller. Several RE doped GaN have inhibitory effects on yellow luminescence and generate red emission peaks. The GaN:La don’t appear photoluminescence peak except for the characteristic peak of GaN. Ce doped GaN appear emission peaks with narrow FWHM between 500~600nm. 5% Pr doping enhances the intrinsic excitation and blue band edge luminescence of GaN. Through the analysis, it can be found that La, Ce and Pr doping influence the grain growth and photoluminescence spectrum of GaN film effectively.

Abstract: The development trend of all solid state lithium ion battery and the importance of lithium ion solid electrolyte in all solid state lithium ion batteries is introduced in this paper. The application of rare earth doping in solid electrolyte of lithium ion battery is summarized. We suggest that rare earth doping is favorable for the increase of the lithium ion battery electrolyte conductivity, thus it is beneficial to further improve the overall performance of all solid state lithium ion battery. The development prospect of rare earth doping in solid electrolyte of all solid state lithium ion battery is looked forward. In addition, we deem that the above mentioned technology is an important research aspect of solid state electrolyte.

Abstract: Preparation technology and measurement technique have get a great achievement in recent years,that lead to the rapid development of upconversion materials.Some of them achieve a higher fluorescence intensity,or get good hydrophily becase of the application of new type of coupling agent.This would help UCNPs closer to the final goal of business application in Solar Cell, biological fluorescence detection,and optical storage.In this paper,I have introduced the basic conception,luminous mechanism, preparation method of UCNPs,and analyzed the different method could bring what special advantages to them in themself’s specific application field.

Abstract: LED as the fourth generation light source has been extensively studied. In order to get a high-performance White Light Emitting Diode (WLED) green phosphor, YPO₄:Ce³⁺,Tb³⁺ was prepared by co-precipitation. It was excited at 380nm. The structure, morphology, fluorescence property and colorimetry of the phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. Final results show the optimal concentration ratio are 1:0.05:0.01. The crystal grain of luminescent material is 200 nm. When the bath temperature is 80°C and calcined at 1000°C for 3h, the luminescence performance of the luminescent material is excellent.

Abstract: _{Subscript text}In this text, Ti/TiO₂-SnO₂ composite electrodes were prepared by Sol-Gel method. Rare earth-doped method can improve the catalytic performance of the composite electrodes. Based on the degradation of oil-field wastewater, e of the electrode surface and the element composition of surface layers were analyzed by SEM, EDX and XRD. When the current density was 30mA/cm², electrode submersed area was 2cm², pH was 3~5, temperature was 30°C and the electrolysis time was 60min, the best treatment process was obtained. The average removal rate of oil content and CODcr were 92.8% and 89.2%, respectively. Under the best treatment process the contaminant was degradated to other intermediate substances during degradation, finally mineralized to CO₂ and H2O.

Abstract: The energy bands of La -doped ZnO were studied systematically by the density functional theory (DFT). Based on the data of the band structure, DOS (Density of State) and PDOS( Partial Density of States), atomic populations and net charge, the influence on the energy band structure of the macrostructure of ZnO and La-doped ZnO was investigated. The results showed that the free electrons were produced by the doping of La on (or in) ZnO crystal. The Fermi energy was shifted up to the conduction band, making the ZnO particles having the characters of degenerated semiconductor. The excitation from impurity states to the conduction band may account for the blue shift of the absorption edge in the model of La-doped ZnO. Comparison with the different models of the La doped/loaded on the ZnO surface, La atoms loaded on the surface of ZnO and La atoms replaced of Zn atoms on the ZnO surface, the shift to the lower energy location were found after La doping/loading. The more shift and the large band gap was found for the model of La doped on the Zn position in the ZnO crystal.

Abstract: We present comprehensive cathodoluminescence measurements from thin amorphous a- SiC films doped with rare earths. The a-SiC films were prepared by rf magnetron sputtering using a high purity SiC wafer in high purity argon atmosphere (5N, pressure approx. 0.2 mbar). The rare earth doping (Tb, Dy and Eu concentrations were below 2%) was performed by placing respective rare earth metal pieces of appropriate size onto the Silicon Carbide wafer. The rare earth ion emissions cover the colors green (Tb), yellow (Dy) and red (Eu). The optical and related structural properties of the films are correlated by means of high resolution transmission electron microscopy in combination with cathodoluminescence measurements in a scanning electron microscope. In addition, the corresponding compositions are determined by energy-dispersive x-ray analysis. The cathodoluminescence spectra of the rare earth 3+ ions are recorded in the visible at 20°C in the asgrown condition and after annealing treatments in the temperature range from 300°C to 1050°C by steps of 150°C. The anneal-related changes in the cathodoluminescence emission spectra and in the microstructure of the films are addressed. The SiC films show amorphous structure almost independent of the annealing treatment. Optimal annealing temperature for emissions of Tb3+ doped a-SiC were derived to be 600°C whereas Dy3+ and Eu3+ emissions increase at least up to 1050°C.

Abstract: Several SiC bulk crystals were grown with erbium and ytterbium as doping materials. Erbium contents determined by secondary ion mass spectroscopy (SIMS) ranged from 1.2 · 1014 cm-3 to 1.04 · 1015 cm-3, while ytterbium contents were below SIMS detection limit. Photoluminescence (PL) investigations of the characteristic 4f-4f-transition lines revealed a reduced luminescence yield in highly nitrogen and aluminum co-doped samples. Also, samples without intentional co-doping grown on the C-face showed less luminescence intensity than those grown on the Si-face. A stabilizing effect of erbium doping on the 4H polytype was observed.