Abstract

The reflectance of evaporated germanium films in the 2650–9000 Å wavelength region is reported, and the effect of evaporation conditions, substrate material, and temperature on the observed reflectance is discussed. An epitaxial film grown on a single-crystal germanium substrate has a reflectance nearly identical to that of an undistorted single-crystal surface. Fine structure is observed including the splitting of the 2.1 eV maximum. However, shoulders which appear at 2.47 and 3.25 eV in the single-crystal results do not appear in the epitaxial film results. Highly oriented polycrystalline films formed at 725°C show the same fine structure as the epitaxial films, but the magnitude of the reflectance in the region of 2 eV is about 3% lower. The reflectance of polycrystalline films formed on substrates at 325°–625°C contains maxima at 4.4 and 2.3 eV, but no fine structure, and amorphous films show only a slight maximum at 4.4 eV. It is possible that crystallite size is important in determining the reflectance spectrum of these films. A room-temperature aging effect was observed with the epitaxial films, which was more pronounced than that observed for polycrystalline and amorphous films.

© 1964 Optical Society of America

Effect of Surface Damage on the Reflectance of Germanium in the 2650–10 000-Å Region

T. M. Donovan, E. J. Ashley, and H. E. Bennett
J. Opt. Soc. Am. 53(12) 1403-1409 (1963)

Optical Constants of Vacuum-Evaporated Silver Films*

R. H. Huebner, E. T. Arakawa, R. A. MacRae, and R. N. Hamm
J. Opt. Soc. Am. 54(12) 1434-1437 (1964)

Ellipsometric study of thermally evaporated germanium thin film

H. Rafla-Yuan, J. D. Rancourt, and M. J. Cumbo
Appl. Opt. 36(25) 6360-6363 (1997)

Infrared Reflectance of Evaporated Aluminum Films

H. E. Bennett, Jean M. Bennett, and E. J. Ashley
J. Opt. Soc. Am. 52(11) 1245-1250 (1962)

Anomalous Optical Effects in Germanium Films

John E. Davey and Titus Pankey
J. Opt. Soc. Am. 56(10) 1331-1337 (1966)