Field Stimulated Surface Diffusion of Lithium on Germanium (100) and (111) Planes

Abstract

Field stimulated surface ditfusion of lithium on atomically clean (100) and (111) germanium single crystal planes has been investigated by means of field emission metlod. Sealed-off field emission tube with a channel multiplier was used. The surface density of lithium adatoms on the germanium surface was determined applying a standard tungsten (112) crystal plane. Tle dependences of the surface diffusion activation energy on the applied electric field at ditferent lithinm coverages lave been obtained. The initial dipole moment of Li adatoms on the Ge (100) and (111) planes was then determined. The values 1.3 ± 0.2 and 1.0 ± 0.2 debye obtained for the Li-Ge (100) and Li-Ge (111) systems respectively are in good agreement with the ones calculated from the work function measurements. The reverse effect of the field influence on the surface diffusion of lithium on Ge (100) and (111) planes has been observed as the second lithium layer is filling. Relative contributions of the peculiarities of semiconductor substrate and alkali adsorbate on the properties of adsystems are discussed on the basis of experimental results. PACS numbers: 79.70.+q, 68.35.Fx