Reference : Preparation and study of 2-D semiconductors with Dirac type bands due to the honeycom...
Scientific congresses, symposiums and conference proceedings : Paper published in a journal
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/10993/20323
Preparation and study of 2-D semiconductors with Dirac type bands due to the honeycomb nanogeometry
English
Kalesaki, Efterpi mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit > ; IEMN- Dept. ISEN, UMR CNRS 8520, Lille, France]
Boneschanscher, M. P. [University of Utrecht, The Netherlands]
Geuchies, J. J. [University of Utrecht, The Netherlands]
Delerue, Christophe [IEMN- Dept. ISEN, UMR CNRS 8520, Lille, France]
Morais Smith, Cristiane [University of Utrecht, The Netherlands > Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena]
Evers, W.H. [Delft University of Technology, The Netherlands]
Allan, Guy [IEMN- Dept. ISEN, UMR CNRS 8520, Lille, France]
Altantzis, Thomas [EMAT, University of Antwerp]
Bals, S. [EMAT, University of Antwerp]
Vanmaekelbergh, Daniel [Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands]
7-Mar-2014
Proceedings of SPIE
International Society for Optical Engineering
8981
Proc. SPIE 8981, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices III, 898107
Yes
International
0277-786X
1996-756X
Bellingham
WA
SPIE Photonics West
from 01-02-2014 to 06-02-2014
SPIE
San Fransisco
USA
[en] The interest in 2-dimensional systems with a honeycomb lattice and related Dirac-­type electronic bands has exceeded the prototype graphene [1]. Currently, 2-­dimensional atomic [2,3] and nanoscale [4-­8] systems are extensively investigated in the search for materials with novel electronic properties that can be tailored by geometry. The immediate question that arises is how to fabricate 2-­D semiconductors that have a honeycomb nanogeometry, and as a consequence of that, display a Dirac-­type band structure? Here, we show that atomically coherent honeycomb superlattices of rocksalt (PbSe, PbTe) and zincblende (CdSe, CdTe) semiconductors can be obtained by nanocrystal self-­assembly and facet-­to-­facet atomic bonding, and subsequent cation exchange. We present a extended structural analysis of atomically coherent 2-­D honeycomb structures that were recently obtained with self-assembly and facet-­to-­facet bonding [9]. We show that this process may in principle lead to three different types of honeycomb structures, one with a graphene type-­, and two others with a silicene-­type structure. Using TEM, electron diffraction, STM and GISAXS it is convincingly shown that the structures are from the silicene-­type. In the second part of this work, we describe the electronic structure of graphene-­type and silicene type honeycomb semiconductors. We present the results of advanced electronic structure calculations using the sp3d5s* atomistic tight-­binding method10. For simplicity, we focus on semiconductors with a simple and single conduction band for the native bulk semiconductor. When the 3-­D geometry is changed into 2-­D honeycomb, a conduction band structure transformation to two types of Dirac cones, one for S-­ and one for P-­orbitals, is observed. The width of the bands depends on the honeycomb period and the coupling between the nanocrystals. Furthermore, there is a dispersionless P-­orbital band, which also forms a landmark of the honeycomb structure. The effects of considerable intrinsic spin-­orbit coupling are briefly considered. For heavy-­element compounds such as CdTe, strong intrinsic spin-­‐orbit coupling opens a non-­trivial gap at the P-orbital Dirac point, leading to a quantum Spin Hall effect [10-­12]. Our work shows that well known semiconductor crystals, known for centuries, can lead to systems with entirely new electronic properties, by the simple action of nanogeometry. It can be foreseen that such structures will play a key role in future opto-­electronic applications, provided that they can be fabricated in a straightforward way.
Researchers ; Professionals ; Students ; General public ; Others
http://hdl.handle.net/10993/20323
10.1117/12.2042882
http://dx.doi.org/10.1117/12.2042882

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