Hole subband structure under strong band bending such a Pb on Si(111) and Indium on Si(111) have been investigated by angle-resolved photoelectron spectroscopy(ARPES). Energy levels of hole subband structure which indicate the quantized levels in inv
ersion layer are strongly depend on band bend shape which can be controlled by the impurity concentration of substrate. Meanwhile, the discrepancy for the suband energy separation between experimental results and calculation results is also observed. In this study, we aim to clarify the relationship between flash annealing and impurity concentration and the hole subband. From this results, it was found out that high temperature flash annealing at 1250 degree has considerable effect on the impurity concentration at subsurface region by Secondary Ion Mass spectroscopy (SIMS) and our diffusion model. This effect makes the band bend shape and subband energy separation change. Moreover, It was revealed that the reduction of the impurity distribution was inhibited less than 900 degree of the flashing temperature.
We investigate the valence band structure of Pb on Ge(001) by Angle-Resolved Photoelectron Spectroscopy. Three Ge bands, G1, G2, and G3, were observed on Ge(001) 2x1 clean surface. In addition to these three bands, a forth band (R band) is found in t
he 2 ML of Pb coverage. The R band continues to appear even when the surface superstructure changed. The position of the R band does not depend on Pb coverage. These results indicate that the R band derives from Ge subsurface states known as surface resonance states. Furthermore, the effective mass of G3 is significantly reduced when this forth band exists. We found that this reduction of the G3 effective mass was explained by the interaction of the G3 and the surface resonance band. Consequently, the surface resonance band penetrates the Ge subsurface region affecting the Ge bulk states. We observed the hybridization between Ge states and the surface resonance states induced by Pb adsorption.
