Crystallization of highly oriented ZnO microrods on carboxylic acid-terminated SAMs

Highly oriented microrods ZnO crystals having a narrow size distribution were successfully crystallized on Si wafers coated with SiCl3(CH2)(11)-O-C6H4-COOH. The relationship between surface properties and the crystallization products was investigated by ellipsometry, wetting measurements, X-ray reflectivity (XR), and grazing incidence diffraction (GID). The influence of the phenyl ether chromophore and the carboxylic group were explored by comparing the crystallization products obtained on monolayers made from SiCl3(CH2)(11)-O-C6H4-COOCH3, SiCl3(CH2)(16)-COOH, and SiCl3(CH2)(16)-COOCH3 molecules. The results demonstrate that the carboxylic acid end group is crucial for achieving a highly oriented growth.