Morphology of nanostructured semiconductors studied using atomic force microscopy combined with stochastic signal spectroscopy

Nano-structured semiconductors obtained by porosifying monocrystalline materials in electrochemical bath are the subject of intensive research due to their specific quantum-mechanical properties and emerging applications. To characterize their morphology, electron microscopy (SEM and TEM) and scanning probe microscopy (STM and AFM) have been used, providing qualitative rather than quantitative knowledge on the porosity, pore wall size and pore alignment. We have applied space series analysis which has been developed within the framework of Stochastic Signal Spectroscopy (3S) to the digitalized images of surface and cross sections of nanostructured inorganic (porous silicon) and organic (polyaniline) semiconductors. We show that SPM/3S study yields quantitative information about alignment of the pores, depth-dependent pore structure and other issues which were not considered before adequately to their importance.