Double-hole-mediated coupling of dopants and its impact on band gap engineering in TiO2

A double-hole-mediated coupling of dopants is unraveled and confirmed in TiO2 by density-functional theory calculations. We find that when a dopant complex on neighboring oxygen sites in TiO2 has net two holes, the holes will strongly couple to each other through significant lattice relaxation. The...

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Bibliographic Details
Published in:Physical review letters 2011-02, Vol.106 (6), p.066801-066801
Main Authors: Yin, Wan-Jian, Wei, Su-Huai, Al-Jassim, Mowafak M, Yan, Yanfa
Format: Article
Language:English
Subjects:
Absorption
band gap engineering
double-hole-mediated coupling
Engineering
Models, Molecular
Molecular Conformation
Oxygen - chemistry
Quantum Theory
semiconductors
SOLAR ENERGY
TiO2
Titanium - chemistry
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Summary:A double-hole-mediated coupling of dopants is unraveled and confirmed in TiO2 by density-functional theory calculations. We find that when a dopant complex on neighboring oxygen sites in TiO2 has net two holes, the holes will strongly couple to each other through significant lattice relaxation. The coupling results in the formation of fully filled impurity bands lying above the valence band of TiO2, leading to a much more effective band gap reduction than that induced by monodoping or conventional donor-acceptor codoping. Our results suggest a new path for semiconductor band gap engineering.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.106.066801