CaF[sub 2] overlayers to preserve the ideal termination of Sb/GaAs(110)

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)

DOI:https://doi.org/10.1116/1.579184· OSTI ID:7084998

Green, A M; Spicer, W E ^[1]; Kim, C; Cao, R; Pianetta, P ^[2]

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1. Stanford Electronics Laboratory, Stanford University, Stanford, California 94305 (United States)
2. Stanford Linear Accelerator Center, Stanford, California 94305 (United States)

Photoemission spectroscopy has been performed on CaF[sub 2] overlayers on as cleaved ( bare'') GaAs(110) and GaAs(110) terminated with 1 monolayer of Sb. We observe Fermi-level positions of 0.7 and 0.9 eV above the valence-band maximum on [ital n] type for the bare and Sb terminated surfaces, respectively. On [ital p] type, we observe close to flatbands for both surfaces. These Fermi-level positions are 0.45 eV on [ital n] type and 0.8 eV on [ital p] type, below previous reports for CaF[sub 2] on the bare surface. We obtain positions close to the previous results by exposing the sample to a flux of UV photons. Upward Fermi-level movement is observed on [ital n] and [ital p] type for both surfaces. Several complimentary experiments will be discussed which indicate that the observed Fermi-level movement is not due to surface charging. We present a possible interpretation of the data which involves a low density of interface states created by the CaF[sub 2] deposition and the formation of F centers when the sample is exposed to UV radiation. Analysis of core-level line shapes suggests the presence of Ga--F bonding for CaF[sub 2] on the bare surface. We present results which indicate that the ideal Sb termination is preserved for CaF[sub 2] on Sb terminated GaAs and evidence of CaF[sub 2]--Sb bonding will be discussed.

• OSTI ID: 7084998
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States) Vol. 12:4; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANTIMONY
ARSENIC COMPOUNDS
ARSENIDES
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CHEMICAL BONDS
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRONIC STRUCTURE
ELEMENTS
EMISSION
ENERGY LEVELS
F CENTERS
FERMI LEVEL
FLUORIDES
FLUORINE COMPOUNDS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INTERFACES
LAYERS
METALS
PASSIVATION
PHOTOEMISSION
PNICTIDES
POINT DEFECTS
SECONDARY EMISSION
VACANCIES