Comparative study of surface morphology of copper phthalocyanine ultra thin films deposited on Si (111) native and RCA-cleaned substrates

Abstract

Comparative study of substrate doping influence on surface morphology of 16-nm CuPc ultra-thin layers deposited on RCA-cleaned Si (111)/SiO2 substrates was carried out. The structure and the morphology of thin films were investigated by X-ray photoelectron spectroscopy and atomic force microscopy. The investigations were aimed to provide information whether substrate doping type can be used as one of the parameters for engineering of the sensing layers structure. Atomic force microscopy images and results of photoemission experiments did not reveal any significant differences in morphology and surface chemistry between used substrates. Observed differences in surface morphology of organic overlayer could be caused by different substrate doping. The CuPc film grown on p-type RCA-Si (111) shows a compact network of densely packed crystallites, while the CuPc film deposited on n-type RCA-Si (111) reveals a slightly more open network of larger crystallites. These observations are confirmed by values of roughness, which is 0.97nm and 1.47nm for CuPc film on RCA-cleaned p- and n-type substrates, respectively. Results were compared with data obtained for similar 16-nm-thick CuPc layers deposited on n- and p-type Si (111) covered with native oxide. Good agreement between results of both studies was found out.