Non-contact atomic force microscopy investigation of the (1 × 1) and (√3 × √3) phases on the Pb/Si(111) surface

Abstract

The (1 × 1) and (√3 × √3) phases of the Pb/Si(111) surface are investigated at room temperature using noncontact atomic force microscopy. The topographic height difference between these phases is determined to be 1.6±0.1 A, which is larger than the theoretical value (1.2 A) previously predicted. Kelvin probe force microscopy measurements show that the work function on the (1 × 1) region is 201±16 meV higher than that on the (√3 × √3) region. The effective dipole moments by electron transfer from the first layer Si atom to the Pb adatom on the (1× 1) phase is discussed. We also succeed in obtaining atomically resolved images of the two phases, and demonstrate that the (1 × 1) phase has small atomic corrugation compared with the (√3 × √3) phase when imaging at same tip condition and the same acquisition parameters. © 2007 The Surface Science Society of Japan.