The surface morphological properties of organic and inorganic material systems have been investigated at nano-scale and correlated to their structural properties. In order to exemplify the organic material characterization, B5 and B19 growth cones from Helisoma Trivolsis buccal ganglion have been studied by Atomic Force Microscopy (AFM) and Phase Contrast Microscopy (PCM) experiments. During the development and the regeneration of the nervous system, the growth cones are responsible for executing dynamic processes such as: Electrochemical surveying of the environment and navigation by engaging environmental guidance cues to locate an appropriate synaptic partner while controlling material assembly required for neurite extension. The extension mechanisms of growth cones are based on two types of processes: fine, finger-like extensions called filopodia and thin, sheet-like protrusions called lamellipodia. The results of AFM experiments have been used to construct 3D architecture model for filopodia. Tapering behaviours of B5 and B19 filopodia have been found to be changing as functions of length. The volumetric information has been used to calculate the number of Ca2+ ions contained in different types of filopodia and the findings have been used for the theoretical evaluation of the electrochemical sensitivity. The results of AFM and PCM experiments have been analyzed in comparative mode to map internal matter distribution on B19 growth cones. In order to exemplify inorganic material characterization, the surface morphological properties of InGaN semiconductor alloys have been studied. InGaN alloy system is a promising base material for device applications operating from UV (3.4 eV) to NIR (0.7 eV). The surface morphology of a semiconductor is defined by overall contributions of surface processes, defects and dislocations. For this reason, nanoscopic investigation of surface morphology reveals information about all these factors affecting macroscopic optical and electrical properties of the layers. The modifications on surface morphology by changing precursor ratio and composition have been investigated and the findings have been correlated to the results obtained from real-time observations and ex-situ characterization experiments. The phase stability of InGaN layers has also been analyzed in relation to the growth temperature and the precursor ratio.

KEYWORDS: Atomic Force Microscopy, Surface morphology, Structural properties, Neural growth cones, Filopodia, InGaN, Epilayers.