Controllable growth of copper-phthalocyanine thin film on rough graphene substrate

摘要

Film growth behavior of copper-phthalocyanine (CuPc) on rough graphene (RG) and smooth graphene (SG) substrates was investigated experimentally. Both the RG and the SG are single layer graphene on metal substrates. The RG samples were prepared on copper foils and show rough surfaces; whereas, the SG samples prepared on Ni(111) substrates are characterized with much smoother surfaces. While CuPc molecules deposited on the two graphene substrates show similar molecular alignment, morphologies of the deposited films show considerable differences. On the SG substrate, CuPc molecules form two-dimensional islands with large size and sharp edges. While on the RG substrate, CuPc nucleates into particle-like grains without regular shapes. The high density of topographical defects on the RG substrate is believed to be a primary factor which leads to the formation of the smaller grains. The variation of thin film structures of CuPc with respect to the substrate temperature was also studied. Films with good crystallinity can still be obtained on the RG substrates when the substrate temperature is 80 °C or higher.