Structural and electronic properties of Bi/GaAs(110)
Ordered Bi overlayers on GaAs(110) were investigated with scanning tunneling microscopy (STM), STM spectroscopy, low-energy electron diffraction (LEED) studies, and with angle-integrated and angle-resolved photoemission spectroscopies. Two-dimensional (2D) layer growth occurs to /similar to/1 monolayer (ML), thereafter three-dimensional (3D) growth dominates. A Bi phase pseudomorphic with the GaAs is observed to /similar to/10 ML. Interdiffusion or chemical reactions between the components were not detected. STM images for coverages of 0.5 and 1 ML reveal the Bi structure to consist of chains of atoms aligned above and in between the Ga--As zigzag surface chains. Additional evidence for dual bonding sites of the Bi suggests that the Bi chains exhibit a zigzag structure similar to the Sb/GaAs system. Near 1 ML the Bi chains are interrupted by a periodic array of dislocations, /similar to/25 A apart, that consist of missing Bi atoms. STM spectroscopy reveals that the Bi ML is semiconductorlike with a 0.7-eV band gap, and that the dislocations generate a band of empty, acceptorlike states within this gap. Band bending measurements indicate that the position of the Fermi level on /ital n/-type GaAs is determined by these acceptor states. Gap states were also associated with Bi terrace edges for coverages /lt/1 ML. The position of the Fermi level for Bi on /ital p/-type GaAs is determined by the top of the Bi valence band, which overlaps that of GaAs by 0.4 eV. The dispersion of this band and another lower Bi band were measured using angle resolved photoemission spectroscopy.
- Research Organization:
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598(US)
- OSTI ID:
- 5951726
- Journal Information:
- J. Vac. Sci. Technol., B; (United States), Journal Name: J. Vac. Sci. Technol., B; (United States) Vol. 7:4; ISSN JVTBD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electronic and structural properties of a discommensurate monolayer system: GaAs(110)-(1/times/1)Bi
Transition metals on GaAs(110): A case for extrinsic surface states
Related Subjects
360602 -- Other Materials-- Structure & Phase Studies
360603* -- Materials-- Properties
ARSENIC COMPOUNDS
ARSENIDES
BISMUTH
COHERENT SCATTERING
CRYSTAL GROWTH
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY GAP
ENERGY LEVELS
FERMI LEVEL
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INTERFACES
LAYERS
METALS
MICROSCOPY
PHOTOELECTRON SPECTROSCOPY
PNICTIDES
SCATTERING
SPECTROSCOPY
SURFACE PROPERTIES