Excitonic effects at the temperature-dependent direct bandgap of Ge
Abstract
The temperature dependence of the complex dielectric function ϵ1+iϵ2 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 k⋅p theory and literature values for effective masses, reasonable agreement with the experiment is obtained for ϵ2 up to room temperature using the direct bandgap and its broadening as the only adjustable parameters.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 25, 2022
- Source ID
- 10.1063/5.0080158
Entities
People
- Carola Emminger
- Farzin Abadizaman
- Jose Menendez
- Melissa Rivero Arias
- Nuwanjula S. Samarasingha
- Stefan Zollner
Organizations
- Air Force Office of Scientific Research
- Arizona State University
- Masaryk University
- National Science Foundation
- New Mexico State University