title: Disorder and suppression of quantum confinement effects in Pd nanoparticles.
abstract: Size-selectable ligand-passivated crystalline and amorphous Pd nanoparticles (<4 nm) are synthesized by a novel two-phase process and verified by high-resolution transmission electron microscopy. Scanning tunneling spectroscopy preformed at 5 K on these two types of nanoparticles exhibits clear Coulomb blockade and Coulomb staircases. Size dependent multipeak spectral features in the differential conductance curve are observed for the crystalline Pd particles but not for the amorphous particles. Theoretical analysis shows that these spectral features are related to the quantized electronic states in the crystalline Pd particle. The suppression of the quantum confinement effect in the amorphous particle arises from the reduction of the degeneracy of the eigenstates and the level broadening due to the reduced lifetime of the electronic states.
authors.affiliation: Structure Research Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China. jghou@ustc.edu.cn
authors.forename: J G
authors.initials: JG
authors.lastname: Hou
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Jinlong
authors.initials: J
authors.lastname: Yang
authors.forename: Kedong
authors.initials: K
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Li
authors.forename: Haiqian
authors.initials: H
authors.lastname: Wang
authors.forename: D M
authors.initials: DM
authors.lastname: Chen
authors.forename: Qingshi
authors.initials: Q
authors.lastname: Zhu