Role of surface reconstruction and passivation mechanisms on the structural and electronic properties of diamond surfaces

Diamond is an insulating material in the bulk form which can exhibit two-dimensional p-type conducting characteristics when its surface is passivated with hydrogen. It is postulated that the formation of a conducting channel at the hydrogenated surface is mainly due to charge transfer between the surface and atmospheric adsorbates. A fundamental understanding of the source of p-type conductivity at the hydrogenated surface is key to the realization of diamond surface field effect transistor (FET). Though there have been many experimental studies in this direction, theoretical studies correlating surface termination and reconstruction to structural and electronic properties have been limited. To address these fundamental questions, we have utilized ab initio density functional theory (DFT) and performed systematic studies of surface reconstruction phenomena in (100) and (110) diamond surfaces. Based on the observed structural and electronic properties, we have made an attempt to establish a correlation between the surface reconstruction and passivation with the electronic properties of the diamond surfaces, such as surface energy, electron affinity, and effective mass.