The Determination of Optical Properties and Energy Gap of Pb(1-X)Sn(X)Te Thin Films in the Fundamental Absorption Edge Region
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The optical properties of single-crystal Pb1-xTe thin films in the fundamental absorption edge region were investigated. Tin compositions of 0 or x or 0.24, where x is the mole fraction of SnTe, were studied from room to liquid nitrogen temperatures. Two thin film samples with x 0.70 and x - 0.85 were also studied in an attempt to confirm the inversion of the conduction and valence bands which had been previously predicted for this narrow-gap semiconductor. The index of refraction n and the absorption coefficient alpha were determined from transmission and reflection measurements made on films 0.8 to 5.0 microns thick, which were deposited on cleaved 100 faces of KCL rocksalt substrates. The optical energy gap was determined from the position of the absorption edge in the absorption spectrum. The index of refraction was obtained using the interference fringe method.
- Solid State Physics