Local work function of a rutile TiO_2(1 1 0)-(1 x 1) surface observed by Kelvin probe force microscopy

摘要

The work function of an atomically flat TiO_2(1 1 0) surface was mapped with a lateral resolution of several nanometers by using a Kelvin probe force microscope. Islands crystallized on an extended terrace exhibited larger work functions than those of the terrace itself. The increment of the work function was dependent on the size of each island; a small island presented an enhanced increment. Laterally oriented electric dipole moments are proposed on single-height steps terminating the islands to interpret the size-dependent increment of the work function.