Cyclic voltammetry for morphological analysis of InGaN epitaxial layers and nanostructures

We introduce cyclic voltammetry (CV) with dissolved, chemically stable electrolytes as a sensitive, non-destructive and fast method for the analysis of the surface morphology of InGaN epitaxial layers and nanostructures grown on silicon. The surface area is probed by the electric double layer capacitance (EDLC) formed upon attachment of ions in solution under close-to-equilibrium conditions. The dynamics of the measured EDLC as a function of scan rate characterizes the nano-scale surface morphology. The dynamics of the measured EDLC follows a power law dependence on the scan rate. The exponent clearly correlates with the RMS surface roughness at the nano/atomic scale deduced from atomic force microscopy. CV is thus complementary to other established methods for the morphological analysis of epitaxial layers in general.