Metal-derived band gap states: Ti on GaAs(110)

Journal Article · Thu May 01 04:00:00 EDT 1986 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.573799· OSTI ID:5726817

Ludeke, R; Straub, D; Himpsel, F J; Landgren, G

The emergence of filled and empty Ti-derived interface states in the band gap of GaAs has been observed for coverages as low as 0.03 monolayer with synchrotron radiation excited photoemission (XPS) and inverse photoemission (IPS) spectroscopies. The onset of the photoelectron threshold for filled states in the valence band spectra and of the IPE photon threshold for the empty states follow directly the position of the surface Fermi level in the band gap. The origin of these states is associated with the rehybridization of the Ti-3d electrons with the valence electrons of the Ga and As atoms of the interface. This notion is supported by XPS core level studies, which show the occurrence of exchange reactions between the Ti and Ga, and the out-diffusion of As and its reaction with Ti. Chemical rebonding at the interface, which produces bonding (filled) and nonbonding (empty) states, is thus the first demonstrable mechanism for Fermi level pinning and Schottky barrier formation.

• Research Organization: IBM T.J. Watson Research Center, Yorktown Heights, New York 10598
• OSTI ID: 5726817
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 4:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
42 ENGINEERING
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
ARSENIC COMPOUNDS
ARSENIDES
BREMSSTRAHLUNG
CHEMICAL BONDS
ELECTROMAGNETIC RADIATION
ELECTRONIC STRUCTURE
ELEMENTS
EMISSION
ENERGY GAP
ENERGY LEVELS
FABRICATION
FERMI LEVEL
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INTERFACES
METALS
PHOTOEMISSION
PNICTIDES
RADIATIONS
SCHOTTKY BARRIER DIODES
SECONDARY EMISSION
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SYNCHROTRON RADIATION
TITANIUM
TRANSITION ELEMENTS
VALENCE