Effect of Gold Roughness on Growth of Copper Phthalocyanine

Metallo-phthalocyanine-based thin films have found diverse applications, in field-effect transistors, gas sensors, and photovoltaic devices. The device performance and electrical properties depend on the orientation of the planar molecule with respect to the substrate. It had been previously found that the molecular plane adheres parallel to a metallic surface, whereas the metal-centers attach to themselves on insulating substrates forming a standing configuration. Here, the effect of gold roughness is examined using atomic force microscopy (AFM) and x-ray diffraction (XRD). Samples were co-deposited at room temperature with 20~nm of CuPc ensuring identicall conditions. The Au roughness was varied by depositing it either onto Cr or Si and by modifying the Au thickness from 12~nm to 50~nm. The change in thickness for the Au/Si substrates caused a change in the roughness of the CuPc from 5.8~nm to 2.3~nm. Crystallo-graphic peaks from x-ray diffraction showed a crystalline peak of 13.0~\AA~at 6.8$^o$ for all samples. The surface morphology and grain size, however, was unaffected.