Synthesis and luminescence properties of erbium-doped y₂O ₃ nanotubes

Erbium-doped yttrium oxide nanotubes (Er³⁺:Y₂O ₃ NTs) with 0-100% doping levels were synthesized by a hydrothermal procedure followed by a dehydration process from Er³⁺:Y(OH) ₃ NTs. The as-synthesized Er³⁺:Y₂O₃ 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 Er³⁺:Y₂O₃ NTs, making them promising for optical amplifier, laser, and active waveguide applications in telecommunications.