Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

230 Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications

© 2011 by Taylor & Francis Group, LLC

The parameter α reects the relative size of the capacitance due to the double layer and the hydroxyl

groups. This is equivalent to the parameter dened by Reference 44, and the concept of a “parallel

capacitance” C

a

and the concept of an “intrinsic buffer capacity” are identical descriptions of the

effect of the site binding. The potential δψ

m

has to be calculated separately; it depends on the eld

just outside the oxide surface, and so is determined by the charge in the semiconductor and on the

oxide surface.

Equations ...