Molecular Imaging and Local Density of States Characterization at the Si(111)/NaOH Interface

We present in situ scanning tunneling microscopy (STM) images with the resolution of isolated ≡Si---OX groups on H-Si(111) in NaOH solutions with or without isopropyl alcohol [X=Hor---CH(CH₃)₂]. The comparison of STM with geometric contours shows that the electronegativity of OH ligands enhances the local density of states and generates a surface potential distribution. The dependence of both observations with the radical X and the mechanisms of grafting are discussed.