A study was conducted of the electrochemical impedance spectroscopy (EIS) response of n-type (similar to 10(18) cm(-3) donor density) nanoporous 6H-SiC (PSC) with a similar to 2000 nm porous layer created by anodic HF etching and non-porous SiC (NSC) controls in NaCl and Na2SO4 electrolytes. At intermediate potentials, PSC had much larger interfacial capacitance than the controls, consistent with the large effective area of the porous material. At high frequencies, the PSC showed transmission line behavior in approximate agreement with predictions of a simplified model that considered the extent and size of porosity and the properties of electrolyte and interface. (c) 2005 Elsevier Ltd. All rights reserved.