Hydrogen-induced metallization on Ge(1 1 1) c(2 × 8)

• Published in: Applied surface science Vol. 252; no. 15; pp. 5300 - 5303
• Main Authors: Razado, I.C., Zhang, H.M., Hansson, G.V., Uhrberg, R.I.G.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 2006; Elsevier Science
• Subjects: Angle-resolved photoelectron spectroscopy; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fysik; Ge c(2 × 8); Hydrogen adsorption; NATURAL SCIENCES; NATURVETENSKAP; Physics; Scanning tunneling microscopy; Scanning tunneling microscopy; 68.35.Bs; 68.43.Fg; Ge c(2 × 8); 79.60.Dp; Angle-resolved photoelectron spectroscopy; 68.37.Ef; Hydrogen adsorption; Angular resolution; Hydrogen; 68.37.Ef; 79.60.Dp; 68.35.Bs; 68.43.Fg; Metallizing; Germanium; Scanning tunneling microscopy; Angle-resolved photoelectron spectroscopy; Hydrogen adsorption; Ge c(2 x 8); Photoelectron spectroscopy
• ISSN: 0169-4332; 1873-5584; 1873-5584
• DOI: 10.1016/j.apsusc.2005.12.062

We have studied hydrogen adsorption on the Ge(1 1 1) c(2 × 8) surface using scanning tunneling microscopy (STM) and angle-resolved photoelectron spectroscopy (ARPES). We find that atomic hydrogen preferentially adsorbs on rest atom sites. The neighbouring adatoms appear higher in STM images, which clearly indicates a charge transfer from the rest atom states to the adatom states. The surface states near the Fermi-level have been followed by ARPES as function of H exposure. Initially, there is strong emission from the rest atom states but no emission at the Fermi-level which confirms the semiconducting character of the c(2 × 8) surface. With increasing H exposure a structure develops in the close vicinity of the Fermi-level. The energy position clearly indicates a metallic character of the H-adsorbed surface. Since the only change in the STM images is the increased brightness of the adatoms neighbouring a H-terminated rest atom, we identify the emission at the Fermi-level with these adatom states.