Influence of Substrate Type and Synthesis Time on Morphological and Structural Properties of Carbon Nanowalls

Abstract In the past decades, carbon nanowalls (CNWs) have attracted great interest due to their specific electronic structure and morphology suitable for optoelectronic, photo‐ and electrochemical systems. This report presents a comparative study on the growth of CNWs on various substrates–quartz (SiO 2 ), stainless steel (SS304), tantalum (Ta), and titanium (Ti) using the capacitively coupled plasma‐enhanced chemical vapor deposition (CCP‐PECVD). It is found that the substrate properties significantly influence the morphology, degree of graphitization, and electrochemical characteristics of the CNWs. SiO 2 provides the lowest defect density and highest structural order, while Ta and Ti promote accelerated CNWs growth due to their high thermal conductivity. Electrochemical tests reveal pronounced photoelectrochemical activity of the CNWs, especially on metallic substrates. Impedance spectroscopy indicates an increase in the electrochemical activity after CNWs growth. The results highlight the importance of substrate selection for controlling the structural and functional properties of the CNWs.