Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 84: Novel Functional Materials I
HL 84.5: Vortrag
Donnerstag, 10. März 2016, 16:30–16:45, H17
Optoelectronic and charge transport properties of Ta3N5 from first principles — •Juliana Morbec1,2 and Giulia Galli1 — 1Institute for Molecular Engineering, University of Chicago, USA — 2Department of Physics, University of Duisburg-Essen, Germany
Tantalum nitride (Ta3N5) is considered a promising material for photoelectrochemical water splitting due to its suitable band gap (∼ 2.1 eV) for visible light absorption and favorable band-edge positions for water splitting. However, Ta3N5 photoanodes have been shown to exhibit poor performance, probably due to their rapid photodegradation and to limitations in their charge transport properties. Using first-principles calculations we carried out a detailed study of the optoelectronic and charge transport properties of crystalline Ta3N5 [1,2]. We present an analysis of the optoelectronic properties of Ta3N5 [1], showing that this material is highly anisotropic, with heavy holes in several directions, pointing to low mobilities. We also discuss the polaronic contributions to the hole and electron mobilities and the effect of stress and substitutional impurities on the electronic structure of Ta3N5 [2]. We show that the overall large effective masses of electrons and holes may be reduced with applied strain.
[1] Juliana M. Morbec, Ieva Narkeviciute, Thomas F. Jaramillo, and Giulia Galli, Phys. Rev. B 90, 155204 (2014).
[2] Juliana M. Morbec and Giulia Galli, 2015 (submitted).
ACKNOWLEDGMENTS: This work was supported by the National Science Foundation under the NSF Center CHE-1305124 for CCI Solar Fuels.