Chemisorption of Ethanol on Ge(100) Surface

Chemical reaction of ethanol (CH₃CH₂OH) with Ge(100) surface has been investigated using scanning tunneling microscopy (STM) observation and density functional theory (DFT) calculations. At low coverage, high-resolution STM images showed that ethanol dissociatively adsorbed on a single Ge dimer. The adsorption features included bright protrusions assigned to Ge-OCH₂CH₃ structure formed via O-H dissociation of ethanol. Real-time STM observations revealed that the molecular chain of ethanol increased gradually via successive adsorption along the dimer row direction following increased exposure to ethanol. DFT calculation results showed that the adsorption of ethanol on Ge(100) was dominated by kinetic control at room temperature. Thus, an integrated study of experimental and theoretical approaches coherently confirmed that ethanol reacts with Ge(100) via O-H dissociative adsorption and the final structure has the H-Ge-Ge-OCH₂CH₃ geometry on a single dimer of Ge(100).