Structure of oxidized bismuth nanoclusters

Abstract

Synchrotron X-ray diffraction has determined that β-Bi2O3 is the dominant oxide phase covering hexagonal bismuth nanoclusters produced in an inert gas aggregation source. Simulated Debye–Scherrer patterns have indicated that the oxide is 20 ± 5 Å thick on average, at the surface of 320 ± 40 Å diameter clusters. A Williamson–Hall analysis of the peak broadening was used to measure the non-uniform strain in clusters. The oxidized clusters were in −0.11 ± 0.06% uniform compressive strain compared with other clusters without oxides detectable by X-ray diffraction which only have a small tensile uniform strain. High-resolution transmission electron microscopy (HRTEM) and multislice image simulations indicated a β-Bi2O3 thickness of 20–50 Å. The HRTEM micrographs show the relative orientation between the oxide and the cluster core.