Nanoengineering with dynamic atomic force microscopy: Lateral interchange of adatoms on a Ge(111)-c(2x8) surface

作者：Dieska Peter; Stich Ivan^*

来源：Physical Review B, 2009, 79(12): 125431.

DOI：10.1103/PhysRevB.79.125431

• ab initio calculations
• atomic force microscopy
• elemental semiconductors
• germanium
• nanotechnology
• surface diffusion
• surface reconstruction

Ab initio techniques are used to elucidate the lateral noncontact AFM pair exchange of Sn and Ge adatoms on the Ge(111)-c(2x8) surface both at low and room temperatures. Two different processes are considered: (a) tip-assisted surface diffusion and (b) active tip participation via adatom pick-up/deposition processes. The adatom diffusion profiles indicate fairly modest energy barriers between 0.6 and 0.8 eV, which can be further significantly reduced by the tip. However, the diffusion-mediated exchange mechanism is precluded by a large barrier (>1 eV) to the (Sn, Ge)-pair exchange. The experimental data are only consistent with a mechanism involving a simultaneous adatom pick-up/deposition and adatom diffusion processes. Simulation results show that, contrary to general belief, the tip apex modification due to the pick-up/deposition processes may not be experimentally noticeable.

• 出版日期2009-3