Ab initio theory of free-carrier absorption in semiconductors

Abstract

The absorption of light by free carriers in semiconductors results in optical loss for all photon wavelengths. Since free-carrier absorption competes with optical transitions across the band gap, it also reduces the efficiency of optoelectronic devices such as solar cells because it does not generate electron-hole pairs. In this work, we develop a first-principles theory of free-carrier absorption taking into account both single-particle excitations and the collective Drude term, and we demonstrate its application to the case of doped Si. We determine the free-carrier absorption coefficient as a function of carrier concentration and we obtain excellent agreement with experimental data. We identify the dominant processes that contribute to free-carrier absorption at various photon wavelengths, and analyze the results to evaluate the impact of this loss mechanism on the efficiency of Si-based optoelectronic devices.

8 pages, 6 figures

References in corpus (6)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials
• Phonon-assisted optical absorption in silicon from first principles
• Theory of the special displacement method for electronic structure calculations at finite temperature
• Theory of electron-plasmon coupling in semiconductors

Cited by in corpus (5)

• Ultrabroadband thin-film lithium tantalate modulator for high-speed communications
• Ab initio calculation of carrier mobility in semiconductors including ionized-impurity scattering
• The Wannier Function Software Ecosystem for Materials Simulations
• Phonon-assisted optical absorption of SiC polytypes from first principles
• Probing carrier and phonon transport in semiconductors all at once through frequency-domain photo-reflectance