Size variation of Tb-doped Gd2O3 nanoparticles studied by X-ray excited luminescence and diffraction

Post-fabrication heat treatment has been found as an effective means for co ntrolling the size distribution of Tb-doped Gd2O3 nanoparticles. Variations in the electronic structure and structural order of these doped quantum do ts are investigated by using the techniques of X-ray excited luminiscence a nd diffraction. From room temperature to 1000 degreesC X-ray powder diffrac tion of this nanoparticle system shows a three-stage transition from featur eless data to that of the bulk crystalline structure with increasing partic le size. However, substantial changes found in the X-ray excited luminescen ce are not directly related to the crystalline structure of the nanoparticl es. These observations also indicate that bulk-like crystalline phase of th e quantum dot material is not a necessary condition for generating the X-ra y induced optical effects which are useful for some technological applicati ons.