Organic/inorganic multilayer hybrid thin films: effect of substrate temperature

New organic/inorganic multilayer hybrid thin films were prepared by electron beam evaporator between two and 10 pairs of CuPc/ZnSe alternating layers. The structural and optical characterisations of multilayer hybrid thin films were carried out using X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and UV-vis absorption spectroscopy. X-ray diffraction patterns show (200) plane as monoclinic CuPc, and (111) and (220) planes as cubic ZnSe structures on the deposited films at room temperature. At the substrate temperature of 150 degrees C, CuPc crystallisation becomes dominant and ZnSe crystallisation is subtle. Nanorod-like CuPc morphology is obtained with increasing substrate temperature. These nanorod-like crystals are arranged mainly with the stacking axis of the CuPc molecules parallel to the substrate surface and nanocrystalline of ZnSe are formed on nanorod indicated through FE-SEM images. The optical absorption spectra are broad, ranging between 420 and 900 nm at room temperature and slightly shift to longer wavelength (520-800 nm) at substrate temperature of 150 degrees C, owing to the nanorod-like structure. The substrate temperature has a direct effect on the structural and optical properties of multilayer hybrid thin films.