Surface stability of NbN single-crystal films
The surfaces of NbN(100) and NbN(111) single-crystal films were analyzed as a function of annealing temperature in ultrahigh vacuum by low-energy electron diffraction and x-ray photoelectron spectroscopy. The NbN(100) surface changed from a (1 x 1) to a ((2)/sup 1/2/ x (2)/sup 1/2/)45/sup 0/ structure at 900/sup 0/C accompanied by a loss of nitrogen. The NbN(111) surface, initially richer in nitrogen, transformed from a (1 x 1) to a (2 x 2) structure at 800/sup 0/C with an even greater loss of nitrogen from the surface. Increasing the carbon content of the films increased the temperatures at which reconstructions were observed. Structural models of the surfaces are presented that are consistent with these observations. At higher temperatures (up to 1100/sup 0/C), additional nitrogen was lost from films of both orientations. Measurements of superconducting transition temperatures and energy gaps indicated that the entire film was nitrogen deficient after annealing, with the greatest nitrogen loss at the surface.
- Research Organization:
- Westinghouse R and D Center, Pittsburgh, Pennsylvania 15235
- OSTI ID:
- 6511536
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 62:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
NIOBIUM NITRIDES
SUPERCONDUCTIVITY
SURFACE PROPERTIES
ANNEALING
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
ENERGY GAP
EXPERIMENTAL DATA
FILMS
IMPURITIES
MONOCRYSTALS
SURFACES
TRANSITION TEMPERATURE
VERY HIGH TEMPERATURE
COHERENT SCATTERING
CRYSTALS
DATA
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HEAT TREATMENTS
INFORMATION
NIOBIUM COMPOUNDS
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SCATTERING
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
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360202 - Ceramics
Cermets
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656100 - Condensed Matter Physics- Superconductivity