High resolution photoemission core level spectroscopy study and TEM analysis of the Ge/As/Si(001) growth

The deposition of 1 ML of As on Si(001)-(2¥1) surface and the heteroepitaxial Ge/As/Si(001)-(2¥1) growth were studied by using high resolution core-level spectroscopy and transmission electron microscopy (TEM). From the spectral decomposition of the Si2p core levels, collected on the Ge/Si interfaces obtained by codepositing As and Ge atoms at different Ge thickness, we identify the contribution of different Si layers to the Si2p lineshape, in agreement with recent theoretical final-state pseudopotential calculations. The bulk-like Ge3d core levels reflected the occurrence of a complete Ge–As site-exchange process, while the pseudomorphic layer-by-layer Ge/Si growth was confirmed by TEM investigation.