Atom-resolved surface chemistry using scanning tunneling microscopy

Abstract

We use scanning tunneling microscopy to investigate the reactivity of the dangling-bond states of Si(111)-(7×7). The reaction with ${\mathrm{NH}}_3$ is used as a prototype. We find that Si rest atoms are more reactive than Si adatoms and that center adatoms are more reactive than corner adatoms. Using atom-resolved electronic spectra, we probe the dangling-bond states on both clean and ${\mathrm{NH}}_3$-exposed surfaces. We find significant interactions and charge transfer between sites which strongly influence surface reactivity.