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Erbium-doped yttrium oxide nanotubes (Er 3+ :Y 2 O 3 NTs) with 0-100% doping levels were synthesized by a hydrothermal procedure followed by a dehydration process from Er 3+ :Y(OH) 3 NTs. The as-synthesized Er 3+ : Y 2 O 3 nanotubes ranged from 100 to 400 nm in outer diameter and 2 to 5 µm in length with a hexagonal cross section. A time-dependent nanostructure evolution study was performed under hydrothermal conditions, and the effects of other processing parameters, including pH, concentration, and ionic strength of the precursor solution as well as the time span for adding the alkaline solution, were found to dictate the purity and morphology of the as-synthesized Er 3+ :Y(OH) 3 nanostructures. A kinetics-controlled dissolution-recrystallization mechanism is proposed to explain the anisotropic growth of these hollow nanotubes from the hexagonal crystal structure of yttrium and erbium hydroxides. Outstanding room-temperature photoluminescence around 1535 nm was demonstrated for these Er 3+ :Y 2 O 3 NTs, making them promising for optical amplifier, laser, and active waveguide applications in telecommunications.

Measurements of the energy loss of fast electrons at an energy of 18 keV have been performed on molecules of hydrogen isotopes, gaseous T2 and frozen D2. Whereas in the case of gaseous T2 the values of total inelastic cross-section (σtot, gaseous = (3.40 ± 0.07) × 10 −18 cm 2 for E = 18.6 keV), average energy loss (εgaseous = (29.9 ± 1.0) eV) and peak position of the energy loss spectra (ε1, gaseous = 12.6 eV) agree well with the expectations, the corresponding values for quench condensed D2 differ significantly from the ones for gaseous T2. We observe a significant lower total inelastic cross-section (σ tot, solid = (2.98 ± 0.16) × 10 −18 cm 2 , for E = 18.6 keV) larger average energy loss (ε solid = (34.4 ± 3.0) eV) and higher peak position (ε 1, solid = (14.1 +0.7 −0.6 ) eV). These differences may be interpreted in terms of changes of the final state spectrum. A CI calculation for a D2 cluster shows indeed a clear shift of the excited states in agreement with the observation. PACS.34.80.Gs Molecular excitation and ionization by electron impact -78.90.+t Other topics in optical properties, condensed matter spectroscopy and other interactions of particles and radiation with condensed matter