Surface Morphology of Bithermal Copper Phthalocyanine Thin Films*

The performance of many semiconducting thin films for photovoltaic and spintronic applications is determined by the interface and surface morphology. Structural control of copper phthalocyanine thin films can be achieved through varying substrate deposition temperature. By consecutively depositing the same material at two different substrate temperatures, referred to as bithermal deposition, novel surface structures are produced and characterized with x-ray diffraction and atomic force microscopy. The x-ray diffraction spectrum has a prominent Bragg peak for all samples, but stronger associated Laue oscillations occur for bilayer samples compared to room temperature deposited copper phthalocyanine thin films. The atomic force microscopy shows two distinct surface morphologies that are unique to the bithermal deposition technique. Via the height-height correlation function, the bithermal samples show lower long-range surface roughness and longer correlation length than room-temperature deposited copper phthalocyanine thin films.