Cathodoluminescent properties at nanometer resolution through Z-contrast scanning transmission electron microscopy

We report the observation of porous structures in laser-ablation-deposited Y2O3:Eu thin films and their correlation with luminescent properties by a c ombination of transmission electron microscopy and Z-contrast scanning tran smission electron microscopy (Z-STEM). Depending on growth conditions, a la rge density of voids is incorporated into the films, which leads to a much increased surface area. Cathodoluminescence imaging in the STEM directly re veals a 5 nm "dead layer" around each void, which is responsible for the ob served reduction in luminescence efficiency. (C) 2000 American Institute of Physics. [S0003- 6951(00)05229-3].