Structural conformations and electronic properties of biphenyl adsorbed on the clean and on the partially hydrogenated Si(1 0 0) surface: An ab initio calculation

First principles density functional calculations have been used to investigate the structural conformations and the electronic properties of biphenyl molecule adsorbed on the clean and on the partially hydrogenated Si(1 0 0) surfaces. The results show that the biphenyl can be adsorbed on several stable conformations on the clean Si(1 0 0) surface and on the Si(1 0 0) surface modified with hydrogens. The biphenyl is chemisorbed on the Si surface with adsorption energies very similar to each other for all conformations. The electronic structure results reveal that the occupied states are quite different for each conformation, while the empty states are very similar to each other, making possible to identify the different conformations only throw occupied states topography. The biphenyl in any conformation on the Si surface does not induce surface conductivity, even when the biphenyls on the Si surface are permitted to bond to each other forming a row of biphenyl molecules.