Density functional theory study of the iron-based porphyrin haem(b) on the Si(111):H surface

作者：Sena Alex M P^*; Brazdova Veronika; Bowler David R

来源：Physical Review B, 2009, 79(24): 245404.

DOI：10.1103/PhysRevB.79.245404

• binding energy
• density functional theory
• elemental semiconductors
• hydrogen
• molecular biophysics
• molecular electronic states
• proteins
• silicon

Iron porphyrins, of which the biological molecule haem(b) is a derivative, have shown potential for use in molecular electronics. Understanding the influence of a surface on a molecules electronic properties is an important step in the assessment of its potential for use in nanoscale devices. Here, a density functional study of haem(b) on the Si(111):H surface has been performed in order to investigate the effect of the molecule-substrate interaction on the electronic structure of haem and provide valuable guidance to current experimental work on this and other like systems. The molecule is found to weakly physisorb onto the surface in a planar conformation at a distance of 3.24 A degrees with a binding energy of 0.42 eV. Creation of a defect in the hydrogen layer of the surface is found to allow the adsorption to strengthen with the binding energy increasing to 0.54 eV and the separation decreasing to 3.05 A degrees. Simulated STM images indicate that the molecule should be visible on the surface and retain its conjugated charge distribution..

• 出版日期2009-6