Regensburg 2002 – scientific programme
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HL: Halbleiterphysik
HL 11: Poster 1
HL 11.28: Poster
Monday, March 11, 2002, 17:00–19:30, Poster A
Room Temperature Photoluminescence and Degradation of PL of SrTiO3:Pr3+, Al Passivated in Hydrogen Plasma — •Stefanie Hartmann1, Duk Jeon2, and Jörg Weber1 — 1Institut für Tieftemperaturphysik, Technische Universität Dresden — 2KAIST, South Korea
Trivalent praseodymium-doped strontium titanates are red emitting phoshors, developed for the use in low-voltage flat panel display devices. Upon UV excitation the samples, prepared by a sol-gel method, show strong luminescence at room temperature. The PL appears as a single, broad peak centered at 617 nm originating from the intra 4f 1D2 ← 3H4 transition of the Pr3+ ions incorporated into the SrTiO3 crystal lattice.
It was found, that the red luminescence is intensified a few hundred times by adding Al or Ga, but there is no full understanding of this phenomenom yet.
After baking the samples to remove organic binders, experiments on hydrogen passivation were carried out. The aim was to investigate whether hydrogen can passivate defects leading to non-radiative recombination channels on the surface or in the bulk material and thus create a further enhancemant of the PL intensity. By varying different parameters such as passivation time, substrate temperature and bias voltage, we obtained a maximum improvement of about 20 % . We observed a partly reversible PL degradation occuring during UV illumination, that was significantly reduced by the hydrogen treatment.