Electrostatic patterning of a silica surface: a new model for charge build-up on a dielectric solid

Rubia F Gouveia; Carlos A R Costa; Fernando Galembeck

doi:10.1021/jp0457601

Electrostatic patterning of a silica surface: a new model for charge build-up on a dielectric solid

J Phys Chem B. 2005 Mar 17;109(10):4631-7. doi: 10.1021/jp0457601.

Authors

Rubia F Gouveia¹, Carlos A R Costa, Fernando Galembeck

Affiliation

¹ Institute of Chemistry, Universidade Estadual de Campinas-UNICAMP, P.O. Box 6154, CEP 13084-971, Campinas - SP, Brazil.

PMID: 16851542
DOI: 10.1021/jp0457601

Abstract

The polarization of interdigitated gold electrodes mounted over a silica thin film formed by oxidation of a Si wafer produces reproducible electrostatic patterns with overall excess negative charge, as observed by scanning electric potential microscopy. Domain charge concentrations as high as 76 charge units per square micrometer are obtained when a 5 V difference is applied to the electrodes thus producing fields in the 10(6) V m(-1) range. These patterns vanish when the electrodes are short-circuited and grounded. Characteristic times for pattern formation and relaxation are in the order of 10 min. The results are consistent with a model based on the discharge of H(+) ions at the negative electrodes, leaving behind immobile surface-bound SiO(-) groups and thus showing that chemisorption phenomena are decisive for electrostatic charging of insulators.