title: Photoinduced interfacial charging and "explosion" of monolayer pentacene islands.
abstract: Electrostatic force microscopy shows that the electric field gradients above pentacene monolayer islands on 2-nm SiO2/Si substrates, in a dark, dry nitrogen environment, display a wide distribution of signs and magnitude that is dependent on sample history. Under 12 mW/cm2 green (532 nm) illumination, pentacene islands accumulate positive charge because of photoexcited electron transfer across the oxide to the Si substrate. At a strong illumination of 60 mW/cm2, pentacene islands reform into small spherical particles, apparently because the positive charge Coulomb repulsion energy becomes comparable to the cohesive energy of the pentacene monolayer.
authors.affiliation: Columbia University, Department of Chemistry, New York 10027, USA. lwchen@helios.phy.ohiou.edu
authors.forename: Liwei
authors.initials: L
authors.lastname: Chen
authors.forename: Oksana
authors.initials: O
authors.lastname: Cherniavskaya
authors.forename: Alexander
authors.initials: A
authors.lastname: Shalek
authors.forename: Louis E
authors.initials: LE
authors.lastname: Brus