Photoemission studies of CdTe(100) and the Ag-CdTe(100) interface: Surface structure, growth behavior, Schottky barrier, and surface photovoltage
The clean CdTe(100) surface prepared by sputtering and annealing was studied with high-energy electron diffraction (HEED) and photoemission. HEED showed the surface to be a one-domain, (2 x 1) reconstruction. Photoemission spectra showed two surface-shifted components for the Cd 4d core level, with an intensity ratio of about 1:3, accounting for nearly an entire atomic layer. No surface-induced shifts for the Te 4d core level were detected. A model is proposed for the surface structure in which the surface layer is free of Te, and Cd atoms form dimers resulting in a (2 x 1) reconstruction; in addition, about (1/4) of the surface area is covered by excess loosely attached Cd atoms. Ag was evaporated on the surface at room temperature and found to grow three dimensionally in the (111) direction. The Ag was found to interact only weakly with the substrate, although the Cd atoms originally loosely bound on top of the surface were found to float on the evaporated Ag islands. A small coverage-dependent surface photovoltage, induced by the synchrotron radiation used for photoemission, was observed; with this effect taken into account, band bending was monitored, the final Fermi-level position being near 0.96 eV above the valence-band maximum. This corresponds to a Schottky-barrier height of about 0.60 eV for the n-type sample used in this experiment. The mechanism for generation of the surface photovoltage will be discussed.
- Research Organization:
- Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- DOE Contract Number:
- AC02-76ER01198
- OSTI ID:
- 5046584
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 34:10
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electronic structure and Schottky-barrier formation on GaAs (100) surfaces prepared by thermal desorption of a protective arsenic coating
Surface photovoltage of Ag on Si(111)-7 times 7 by scanning tunneling microscopy. Technical report No. 1
Related Subjects
CADMIUM TELLURIDES
ELECTRON DIFFRACTION
INTERFACES
PHOTOELECTRON SPECTROSCOPY
PHOTOVOLTAIC EFFECT
SILVER
ADSORPTION
DOPED MATERIALS
EXPERIMENTAL DATA
FERMI LEVEL
INDIUM
N-TYPE CONDUCTORS
SCHOTTKY BARRIER DIODES
SURFACES
SYNCHROTRON RADIATION
BREMSSTRAHLUNG
CADMIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY LEVELS
INFORMATION
MATERIALS
METALS
NUMERICAL DATA
PHOTOELECTROMAGNETIC EFFECTS
RADIATIONS
SCATTERING
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SEMICONDUCTOR MATERIALS
SORPTION
SPECTROSCOPY
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENTS
360605* - Materials- Radiation Effects