Regensburg 2019 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 45: Photovoltaics (joint session HL/CPP)
CPP 45.1: Talk
Wednesday, April 3, 2019, 15:00–15:15, H36
Revisiting the electronic structure of vanadium doped In2S3 — •Elaheh Ghorbani1, Paul Erhart2, and Karsten Albe1 — 1Institut für Materialwissenschaft, Technische Universität Darmstadt, Darmstadt, Germany — 2Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
Transition metal impurities often have noticeable impacts on the electronic and optical properties of the host material. Recently, they have been suggested as intentional dopants for the purpose of creating intermediate metallic bands within the band gap of parent semiconductor. These intermediate bands (IB), if partially filled and optimally placed between valence and conduction bands, can collect photons of sub-band gap energies and enhance the photocurrent density. In this context, the formation of an IB in V-doped In2S3 (In2S3:V) was predicted by first-principles calculations. In this contribution, we revisit In2S3:V, using a band gap corrected method (hybrid functional) and show that V3+ (with 3t2g2eg0 configuration) substituting for octahedral In3+ is a Jahn-Teller active ion. The aroused Jahn-Teller distortion necessitates removing the degeneracy of t2g levels through splitting it into filled e and empty a sublevels, which reside at the top of the valence band and bottom of the conduction band, respectively. Consequently, no IB forms, when both V and In are in 3+ oxidation state. To give a fuller picture of In2S3:V, we studied the rehybridization of V d orbitals with S p orbitals for different oxidation numbers of V. Our results show that in the presence of a reducing agent, like H+, a totally filled t2g level can form inside the gap.