Structure and optical properties of evaporated films of the Cr- and V-group metals

Journal Article · Tue Jan 01 04:00:00 EST 1980 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.327321· OSTI ID:5552766

Nestell, Jr, J E; Christy, R W; Cohen, M H; Ruben, G C

Thin films of Cr, Mo, and W rapidly evaporated in high vacuum (5 x 10/sup -7/ Torr) onto room-temperature substrates show anomalously low reflectance (compared to bulk samples). From electron and x-ray diffraction and electron microscopy, we find the normal bcc crystal structure, but with very fine grains. Columnar grains about 100 A in diameter were separated by a less dense grain-boundary network about 10 A wide. The measured optical conductivity agrees with an inhomogeneous-medium model that assumes the normal crystalline conductivity for the grain interiors, with model parameters that correlate to the observed columnar grain size. In contrast, V and Nb films rapidly evaporated onto room-temperature substrates have the reflectance of bulk crystalline material. On liquid- nitrogen temperature substrates, however, V and Nb have normal bcc crystal structure but with small flat-plate grains, and the same model, with appropriate parameters, accounts for the optical conductivity. The difference between these two groups apparently depends on residual gases segregated at the grain boundaries in the Cr-group films.

• Research Organization: Dartmouth College, Hanover, New Hampshire 03755
• OSTI ID: 5552766
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:1; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
BCC LATTICES
CHROMIUM
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
EVAPORATION
FILMS
HIGH VACUUM
METALS
MICROSCOPY
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
REFRACTORY METALS
SCATTERING
TRANSITION ELEMENTS
TUNGSTEN
VANADIUM
X-RAY DIFFRACTION