RT journal article
T1 Application of the Holomorphic Tauc-Lorentz-Urbach Function to Extract the Optical Constants of Amorphous Semiconductor Thin Films
A1 Ballester, Manuel
A1 García, Marcos
A1 Márquez Lozano, Almudena del Pilar
A1 Blanco Ollero, Eduardo
A1 Fernández, Susana M.
A1 Minkov, Dorian
A1 Katsaggelos, Aggelos K.
A1 Cossairt, Oliver
A1 Willomitzer, Florian
A1 Márquez Navarro, Emilio José
A2 Física de la Materia Condensada
A2 Matemáticas
K1 amorphous semiconductors
K1 dielectric function
K1 optical properties
K1 Tauc–Lorentz model
K1 Tauc–Lorentz–Urbach model
K1 thin-film characterization
AB The Tauc-Lorentz-Urbach (TLU) dispersion model allows us to build a dielectric function from only a few parameters. However, this dielectric function is non-analytic and presents some mathematical drawbacks. As a consequence of this issue, the model becomes inaccurate. In the present work, we will adopt a procedure to conveniently transform the TLU model into a self-consistent dispersion model. The transformation involves the integration of the original TLU imaginary dielectric function epsilon(2) by using a Lorentzian-type function of semi-width, Gamma. This novel model is analytic and obeys the other necessary mathematical requirements of the optical constants of solid-state materials. The main difference with the non-analytic TLU model occurs at values of the photon energy near or lower than that of the bandgap energy (within the Urbach absorption region). In particular, this new model allows us to reliably extend the optical characterization of amorphous-semiconductor thin films within the limit to zero photon energy. To the best of our knowledge, this is the first time that the analytic TLU model has been successfully used to accurately determine the optical constants of unhydrogenated a-Si films using only their normal-incidence transmission spectra.
PB MDPI
SN 2079-6412
YR 2022
FD 2022-10
LK http://hdl.handle.net/10498/28836
UL http://hdl.handle.net/10498/28836
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 10-nov-2026