Charge transfer in the atomic structure of Ge (1 0 5)

Abstract The atomic structure and charge transfer on the Ge (1 0 5) surface formed on Si substrates are studied using scanning tunneling microscopy and spectroscopy (STM and STS). The bias-dependent STM images of the whole Ge (1 0 5) facets formed on a Ge ‘‘hut’’ structure on Si (0 0 1) are observed, which arewell explained by the recently confirmed structure model. The local surface density of states on theGe (1 0 5) surface ismeasured by STS. The localization of the electronic states expected from charge transfer mechanism is observed in the dI/dV spectra. The surface band gap is estimated as 0.8–0.9 eV, which is even wider than the bulk bandgap of Ge, indicating the strong charge transfer effect to make the dangling bonds stable. The shape of normalized tunnel conductance agrees with the theoretical band structure published recently by Hashimoto et al.