It has previously been determined that absorption of infrared radiation in germanium due to free carriers can be controlled to some extent by doping. As a result, the use of germanium in infrared systems can be extended to thermal environments not possible before. This can be accomplished by using lower resistivity germanium at elevated temperatures instead of the standard optical grade germanium used near room temperature (25°). In this work, the absorption of 3 to 11.9 tm radiation by germanium of various resistivities was determined at several discrete temperatures from room temperature to 120°C. The germanium samples ranged in resistivity from 0.1 to 40 ohm-cm. The data from these measurements were used to formulate graphical representations of the relationships between room temperature resistivity, absorption coefficient, wavelength and temperature.

Date Published: 1 October 1990
PDF: 14 pages
Proc. SPIE 1326, Window and Dome Technologies and Materials II, (1 October 1990); doi: 10.1117/12.22488

Published in SPIE Proceedings Vol. 1326:
Window and Dome Technologies and Materials II
Paul Klocek, Editor(s)