Electrochemical impedance study of GaAs surface charge modulation through the deprotonation of carboxylic acid monolayers

Fernanda Camacho-Alanis; Homero Castaneda; Giovanni Zangari; Nathan S Swami

doi:10.1021/la2013107

Electrochemical impedance study of GaAs surface charge modulation through the deprotonation of carboxylic acid monolayers

Langmuir. 2011 Sep 20;27(18):11273-7. doi: 10.1021/la2013107. Epub 2011 Aug 26.

Authors

Fernanda Camacho-Alanis¹, Homero Castaneda, Giovanni Zangari, Nathan S Swami

Affiliation

¹ Electrical Engineering, University of Virginia, Charlottesville, Virginia 22904, USA.

PMID: 21859118
DOI: 10.1021/la2013107

Abstract

Modifications to the space charge region of p+ and p-GaAs due to surface charge modulation by the pH-induced deprotonation of bound carboxylic acid terminal monolayers were studied by electrochemical impedance spectroscopy and correlated to flat-band potential measurements from Mott-Schottky plots. We infer that the negative surface dipole formed on GaAs due to monolayer deprotonation causes an enhancement of the downward interfacial band bending. The space charge layer modifications were correlated to intermolecular electrostatic interactions and semiconductor depletion characteristics.