ZnO Nanorod Arrays by Plasma-Enhanced CVD for Light-Activated Functional Applications

The functional performance of ZnO NRs is directly dependent on the availability of proper synthetic strategies enabling a fine control of their morphology and spatial organization. Among the various approaches, chemical vapor deposition (CVD) is one of the most versatile techniques due to its intrinsic experimental flexibility and to the use of metalorganic precursors endowed with ad hoc chemical and physical properties. In particular, activation of both gas-phase and surface processes by means of non-equilibrium plasmas (plasma-enhanced CVD, PE-CVD) promotes alternative reaction pathways under softer conditions than in thermal CVD, enabling one to modulate deposition surface chemistry and to obtain 1D nanostructures with tailored properties. Herein, we report on the PE-CVD of supported ZnO nanorod arrays on Si(100) substrates from two recently developed bis- (ketoiminato) zinc (II) compounds, Zn[(R’)NC(CH3)= C(H)C(CH3)=O]2, with R’=-(CH2)2OCH3 or -(CH2)3OCH3 . The selective growth of ZnO NR arrays was performed from Ar/O2 plasmas at 200 and 300 °C , the lowest temperatures reported in the literature for the PE-CVD of such 1D architectures. Special attention was devoted to the interrelations between photo-induced superhydrophilicity (PSH) and (photocatalysis) PC activity of the obtained 1D ZnO systems and their morphological characteristics.