Far- and Mid-Infrared Properties of Metal-Insulator Composite Materials
Abstract
The infrared properties of thin Pt/Al2O3 granular metal-insulator composite films (cermets) were investigated using Fourier transform spectroscopy. The films were grown by dual electron beam evaporation onto polished single crystal sapphire substrates. They were borrowed from Dr. J.V. Mantese of General Motors Research Labs. The metallic volume fraction, which was controlled by the deposition conditions, ranged from 23% to 100% in the set of samples. The percolation threshold estimate from the temperature dependence of the dc resistance is greater than 50%, which implies that the Pt particles are highly correlated. The percolation threshold for a random metal-insulator mixture is less than 20%. The transmission and relative reflection of the films were measured at room temperature using a Nicolet 740 Fourier transform infrared spectrometer (FTIR), which arrived at the beginning of the year. The mid and near infrared regions (400-15250 cm-1) were covered using three combinations of sources, beamsplitters, and detectors. The reflection standard was a 100% Pt film from the sample set.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA204914
Entities
People
- Robert P. Devaty
Organizations
- University of Pittsburgh