Hole Subband Dispersion in Space Charge Layers under Pb/Si(001) Surfaces Measured by Angle-Resolved Photoelectron Spectroscopy

The dispersion structure of the hole subband in a p-type space charge layer on Si(001) was investigated for the first time by angle-resolved photoelectron spectroscopy. The space charge layer was made via adsorption of Pb. The dispersion curves were in qualitative agreement with the parabolic dispersion curves with bulk effective masses obtained by the k·p perturbation method. The observed energy levels had smaller binding energy than the levels calculated by the triangle potential approximation. This was interpreted to reflect a change of the dopant atom concentration in the subsurface region due to diffusion of dopant during flashing. [DOI: 10.1380/ejssnt.2009.641]