Morphological and Electrical Characterization of Pillar-Like Structures in Nanodiamond Layers

The self-assembly of pillar-like structures in nanodiamond (ND) layers was obtained by means of the pulsed spray technique. This technique enabled to deposit ND layers directly on silicon substrate using a dispersion of as-received 250 nm nanocrystals. The chemical and structural properties of the ND layer were determined by Raman and photoluminescence spectroscopies and the morphological features were measured by confocal and atomic force microscopies. Self-assembled pillar-like structures were observed by both microscopies. The local electrical voltage and current of an isolated ND pillar were studied by scanning Kelvin probe microscopy and scanning capacitance microscopy (SCM), respectively. The electrical data obtained showed that the single pillar features an increase of voltage and a decrease of current. A theoretical model based on the finite element method confirmed the current behavior measured by SCM.