Characterization of the ZnO-ZnS Interface in THIOL-Capped ZnO Nanoparticles Exhibiting Anomalous Magnetic Properties

This work reports an X-ray absorption near-edge structure spectroscopy (XANES) study at the Zn K-edge in ZnO nanoparticles (NPs) capped with different organic molecules. The analysis of the XANES spectrum of NPs capped with dodecanethiol suggests that several Zn atoms bond to the S atoms of the capping molecule. Indeed, the comparison of the experimental XANES spectra and theoretical computations points out the existence of a ZnO-ZnS interface in which both ZnS and ZnO shows a wurtzite structure. These results support that the exotic magnetism observed in these capped ZnO NPs resides at the hybridized p band formed among Zn and the S bonding atoms in this interface, while the rest of the ZnO NPs behaves as a standard ZnO semiconductor.