STM investigation of porphyrin isomers on metal substrates

We performed scanning tunneling microscopy (STM) experiments on mono- or sub-monolayer deposited porphyrin molecules on metal substrates. We observed substitution-dependent structure changes of the molecules. Obtaining STM images of the structure and arrangement of functional molecules would contribute valuable information towards creation of nano-molecular-devices. scanning probe microscopy (SPM) shows the greatest potential for reaching this goal, at present. STM is able to obtain images with nano-meter resolution of molecules on metal surfaces. These high-resolution images reveal the molecular structure and arrangement of the molecules on the surface and contain information about the molecule–substrate interaction and the molecule–molecule interaction. STM will be useful for the assembly of nano-devices made from molecules on a substrate.