The luminescence of Tb-doped a-SiC:H thin films with different Tb concentrations under sub-bandgap photon excitation was investigated. Two independent processes were identified. The annealing induced activation of the Tb3+ and the inhibition of host-mediated non-radiative recombination paths. The integrated emission intensity is described by a rate equation model, considering these two. In this study, the luminescence enhancement with increasing annealing temperature is shown. The optimal Tb concentration and annealing temperature for the highest Tb-related light emission intensity is determined. Finally, a parameter proportional to the number of optically active ions is found through the aforementioned model.

We present a systematic study of photo- and cathodoluminescence measurements in the visible of Terbium doped SiC:H and AlN thin films. The Terbium atomic concentrations vary from 0.9 to 10% for the SiC:H and from 0.8 to 6% for the AlN samples. For both materials the increase of the emission intensity with concentration and the subsequent quenching effect can be seen. The optimal concentration for the highest light emission is found. Photoluminescence excitation spectroscopy addresses the enhancement light emission mechanisms of the principal emission electronic transition of Terbium at ∼542 nm.

Tb and Yb co-doped oxyfluoride glasses were fabricated in a lithium-lanthanum-aluminosilicate matrix by a melt-quench technique. Glass-ceramics were obtained by appropriate heat treatment of the as-prepared glasses. Visible to near-infrared down-conversion quantum cutting was studied for samples with different thermal annealing temperatures and time. Laser light at 488 nm was used to excite Tb3+ ions while Yb3+ ions were excited by energy transfer from the excited Tb3+ ions. Near-infrared emission at 940 – 1020 nm was observed. It has been found that the emission at 940 – 1020 nm increased significantly from the glass-ceramic compared to that of the as-prepared glass. This result suggests that the energy-transfer efficiency increases in glass-ceramics compared to that in glass. A significant portion of rare-earth ions may be incorporated inside LaF3 nanoparticles (NPs) in the glass-ceramic. Because the Yb3+ emission at 940 – 1020 nm is matched well with the band gap of crystalline Si, the quantum cutting effect may have its potential application in silicon-based solar cells.

Near-infrared quantum cutting involving the conversion of one visible photon into two near-infrared photons was demonstrated in Ca0.99−xYbxWO4: Tb0.01 phosphors. From the analysis of the refinement of x-ray diffraction patterns, the suitable concentration range of Yb3+ in Ca0.99WO4: 0.01Tb3+ was determined to be 0–20%. By investigating their luminescent spectra and decay lifetimes, second-order downconversion from Tb3+ to Yb3+ were proved and the possible quantum cutting mechanism was proposed. Quantum efficiency related to Yb3+ concentration was calculated and the maximum efficiency was reached at 140.4%. Because the energy of Yb3 + 2F7/2 → 2F5/2 transition matches well with the band gap of the crystalline Si, the Ca0.99−xYbxWO4: Tb0.01 phosphors could be potentially applied in silicon-based solar cells.

Thornlike Tb-doped SiC (SiC:Tb) nanostructures were synthesized through a carbothermal reduction of electrospun Tb-doped SiO2 nanofibers (SiO2:Tb). The synthesized SiC nanostructures annealed at a high temperature of 1300 °C displayed a unique morphology and a high crystalline quality with the β-SiC phase. Strong green-light emissions were detected from the SiC:Tb samples. Photoluminescence excitation results show that, besides a small amount of energy coming from the SiC cores (464 nm), most of the energy needed for the excitation of Tb3+ ions comes from the light absorption of the SiO2–Tb surface layers (295 nm) and near-interface regions in the samples (388 nm). Transmission electron microscopy, energy dispersive spectrometry, and Raman analyses suggested that the formations of Tb clusters and SiO2 surface layers are very important to the enhancement of the luminescence behaviors of Tb3+ ions. Finally, we have constructed an excitation model and further proposed an energy transfer mechanism for these thornlike SiC:Tb nanostructures.

Two aluminosilicate oxyfluoride glass systems, a lead-cadmium-aluminosilicate oxyfluoride and a lithium-lanthanum-aluminosilicate oxyfluoride, doped with different TbF3 concentrations, have been fabricated and investigated. By appropriate heat treatment of the as-prepared glasses above, transparent glass-ceramics (TGC) were obtained. The glass-ceramics contain Tb:Pb(Cd)F2 or Tb:LaF3 nano-crystals in the glass-matrix. Differential scanning calorimetry, Raman scattering, and luminescence under both UV and β-particle excitation have been investigated on as-prepared glasses and glass-ceramics. It has been found that the terbium-doped lithium-lanthanum-aluminosilicate oxyfluoride glass exhibits good UV excited luminescence and β-induced luminescence. The luminescence yield increases for glass-ceramic compared to that of the as-prepared glass. The including of LaF3 in the glass-matrix is beneficial for a higher Tb-doping concentration and a high light yield. The light yield of lithium-lanthanum-aluminosilicate oxyfluoride glass and glass-ceramic is comparable to that of Schott IQI-301 product. However, the terbium-doped lead-cadmium-aluminosilicate oxyfluoride glass and glass-ceramic have a detrimental luminescence performance. The lead cations in the glass-matrix may create non-bridging oxygen defects, which are a strong source of charge traps, and correlated to a strong Raman “Boson” peak.

Tb-doped AlBNO (AlBNO:Tb) films with various composition ratios are investigated for luminescence layers of inorganic electroluminescence(EL) devices. Luminescence layers with a wide bandgap and a low dielectric constant are required to realize high performance of EL devices. The ultraviolet-visible radiation absorption measurement and capacitance-voltage (C-V) measurement show that the AlBNO:Tb films have wider bandgap and lower dielectric constant than ZnS which is put to practical use as the host material of the luminescence layer. Photoluminescence (PL) measurement indicates that PL intensity increases with increasing B composition ratio in the range of 5 % - 10 %. Moreover, the suppression factor of the PL intensity can be understood through the annealing experiment. The PL intensity of the film with 800 °C annealing is about 10 times larger than that of the film without annealing. X-ray photoelectron spectroscopy (XPS) measurement suggests that Tb4+ ions decrease compared with Tb3+ ions after annealing treatment. O atoms in the AlBNO:Tb film are dissociated from Tb and bonded to B atoms by annealing treatment. This suggests that decrease of Tb4+ ions is related to increase of the PL intensity.

TbMnO3 is a multiferroic magnetoelectric material known to simultaneously exhibit antiferromagnetism below 40K and ferroelectricity below 28K in the same crystalline phase [1]. Following interesting results of Cu substitution in LaMn1-yCuyO3 [2, 3], we report a study of TbMn1-x CuxO3 (0 < x < 0.15). We describe here our results of crystal structure refinement, together with measurements of magnetic and dielectric properties in the temperature range 2 - 320 K, and magnetic field 0 - 9 T. We find no major changes in structure or symmetry upon substitution of Cu up to x = 0.15 in TbMn1-x CuxO3. Unlike LaMn1-yCuyO3, which exhibits ferromagnetism with very low values of y, we observe antiferromagnetism at x = 0.15. Our study of dielectric properties as a function of temperature suggests increased lossy behavior upon substitution of Cu at the Mn site. In our temperature dependent studies of tan δ at 1 kHz, we observe a well-defined step-like feature near 120K in both pure and substituted samples, possibly ascribable to a change in carrier mobility, or a dielectric-relaxation process mediated by ordered oxygen vacancies [4, 5], which we will continue to study.

In this paper, we report on the multicolor luminescence in oxygen-deficient Tb3+-doped calcium aluminogermanate glasses. A simple method was proposed to control oxygen-deficient defects in glasses by adding metal Al instead of the corresponding oxide (Al2O3), resulting in efficient blue and red emissions from Tb3+-undoped glasses with 300 and 380 nm excitation wavelengths, respectively. Moreover, in Tb3+-doped oxygen-deficient glasses, bright three-color (sky-blue, green or yellow, and red) luminescence was observed with 300, 380, and 395 nm excitation wavelengths, respectively. These glasses are useful for the fabrication of white light-emitting diode (LED) lighting.

Cathodoluminescence (CL) of rare earth (RE) ions implanted AlN/GaN superlattice (SL) structures grown by chemical vapor deposition (CVD) technique on GaN/(0001) sapphire substrate was measured at 10 K and 300 K. Implantation of terbium and thulium in SLs was done at 150 keV with a dose of up to 1×1015 cm-2 at 300 K. Samples were given post implantation isochronal thermal treatment at 900 °C in nitrogen ambient. The interface quality between the SL layers before and after implantation as well as after thermal annealing treatment has been investigated by X-ray diffraction (XRD). The characteristic satellite peaks of the SLs were measured for the (0002) reflection in the symmetric Bragg geometry for the reference, RE-implanted, and annealed SLs. Furthermore, the luminescence intensity of a RE3+ ion doped AlN/GaN SL was compared with the one from RE-implanted GaN epilayers. Despite the structural damage of the AlN/GaN structures, an enhancement of the characteristic emission intensities from RE3+ ions in the SLs was observed compared to emission from RE ions in epilayers.

Vole tuberculosis (TB; Mycobacterium microti) is an understudied endemic infection. Despite progressing slowly, it causes severe clinical pathology and overt symptoms in its rodent host. TB was monitored for 2 years in wild field voles in Kielder Forest, UK. The prevalence of characteristic cutaneous TB lesions was monitored longitudinally at 4 sites, with individuals live-trapped and repeatedly monitored. A prevalence of 5·2% of individuals with lesions was recorded (n=2791). In a cross-sectional study, 27 sites were monitored bi-annually, with TB assessed by post-mortem examination for macroscopic lesions, and by culture and histopathology. Seventy-nine voles (10·78%; n=733) were positive for mycobacteria, with the highest prevalence in spring (13·15%; n=327). TB prevalence varied, with between 0% and 50% of voles infected per site. Prevalence increased with age (mass), and apparent seasonality was due to a higher proportion of older animals in spring. Survival analysis supported this result, with cutaneous lesions only manifesting in the advanced stages of infection, and therefore only being found on older voles. The body condition of individuals with lesions declined at the time when the lesion was first recorded, when compared to individuals without lesions, suggesting there may be an acute phase of infection during its advanced stage. Although predicted survival following the appearance of a cutaneous lesion was lower than for uninfected individuals, this was not significant.

The optical properties of Tb-doped SiO2 films have been studied from multi-wavelength spectroscopic ellipsometry (SE) measurements performed over the 250–1100 nm wavelength range. The SE modeling carried out with care to adhere as much to the ellipsometric fitting qualities. The refractive index dispersions, the layer thickness, and the lateral thickness variation of the films are given and discussed regarding the optical constitution of these films and the ellipsometric validity of these parameters