Band bending at Al, In, Ag, and Pt interfaces with CdTe and ZnTe (110)

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)

DOI:https://doi.org/10.1116/1.576784· OSTI ID:6901506

Wahi, A K; Miyano, K; Carey, G P; Chiang, T T; Lindau, I; Spicer, W E ^[1]

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1. Stanford Electronics Laboratories, Stanford University, Stanford, CA (USA)

Band bending behavior and interfacial chemistry for Al, In, Ag, and Pt overlayers on vacuum-cleaved {ital p}-CdTe and {ital p}-ZnTe (110) have been studied using ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS). These metals provide a range of metal--substrate reactivities: Al reacts strongly with Te, Ag moderately, and In minimally, with no evidence seen for In reaction on ZnTe. Pt exhibits strong alloying behavior with both Cd and Zn. All four metals are found to yield Schottky barriers on CdTe and ZnTe, with a narrow range of final Fermi level positions, {ital E}{sub {ital fi}}={ital E}{sub {ital f}}{minus}{ital E}{sub VBM}, observed on CdTe, from 0.9 to 1.05{plus minus}0.1 eV, and on ZnTe from 0.65 to 1.0{plus minus}0.1 eV. The prediction of the MIGS model that a difference in barrier height exists for two semiconductors dependent upon their band lineup (valence band offset) is examined and found to agree with experiment for Ag, Pt, and Al, but not for In. For the highly reactive Al, no evidence for the overlayer metallicity required for metal-induced gap states (MIGS) to operate is seen on CdTe or ZnTe until after band bending has stabilized. Reaction and intermixing for Al, Ag, and Pt overlayers on CdTe and ZnTe indicate these interfaces are not ideal. The possible role of defects at these four metal/CdTe and metal/ZnTe interfaces is considered, and provides a consistent explanation for the final Fermi level positions observed.

• DOE Contract Number: AC03-82ER13000
• OSTI ID: 6901506
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA) Vol. 8:3; ISSN JVTAD; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALUMINIUM
BAND THEORY
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
ENERGY LEVELS
FERMI LEVEL
INTERFACES
METALS
PLATINUM
PLATINUM METALS
SCHOTTKY EFFECT
SILVER
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENTS
ZINC COMPOUNDS
ZINC TELLURIDES