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Title: Excitonic effects at the temperature-dependent direct bandgap of Ge
The temperature dependence of the complex dielectric function [Formula: see text] of bulk Ge near the direct bandgap was investigated with spectroscopic ellipsometry at temperatures between 10 and 710 K. Second derivatives of the dielectric function with respect to energy are obtained using a digital linear filter method. A model that incorporates excitonic effects using the Tanguy model for the Hulthén potential [C. Tanguy, Phys. Rev. B 60, 10660 (1999)] was used to fit the dielectric function and its second derivatives simultaneously. Using [Formula: see text] theory and literature values for effective masses, reasonable agreement with the experiment is obtained for [Formula: see text] up to room temperature using the direct bandgap and its broadening as the only adjustable parameters.  more » « less
Award ID(s):
2119583
PAR ID:
10340876
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Journal of Applied Physics
Volume:
131
Issue:
16
ISSN:
0021-8979
Page Range / eLocation ID:
165701
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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