1. Electronic structure of atomically coherent square semiconductor superlattices with dimensionality below two
- Author
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Daniel Vanmaekelbergh, Christophe Delerue, Wiel H. Evers, Efterpi Kalesaki, Guy Allan, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), University of Luxembourg [Luxembourg], Delft University of Technology (TU Delft), Debye Institute for Nanomaterials Science, Utrecht University [Utrecht], This work has been supported by funding of the French National Research Agency [ANR, (ANR-09-BLAN-0421-01)]. E.K., C.D., and G.A. performed the calculations. W.H.E performed sample preparation and structural analysis. C.D. was a visiting professor at the Debye Institute for Nanomaterials Science at the time of this research. C.D. and D.V. supervised the project. All authors were involved in writing of the paper., and ANR-09-BLAN-0421,ETSFG(2009)
- Subjects
Materials science ,Spintronics ,Condensed matter physics ,business.industry ,Superlattice ,Physics [G04] [Physical, chemical, mathematical & earth Sciences] ,02 engineering and technology ,Electronic structure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,7. Clean energy ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Atomic coherence ,[SPI]Engineering Sciences [physics] ,Semiconductor ,Physique [G04] [Physique, chimie, mathématiques & sciences de la terre] ,0103 physical sciences ,Nano ,010306 general physics ,0210 nano-technology ,business ,Quantum well ,Curse of dimensionality - Abstract
The electronic structure of recently synthesized square superlattices with atomic coherence composed of PbSe, CdSe, or CdTe nanocrystals (NCs) attached along {100} facets is investigated using tight-binding calculations. In experimental realizations of these systems [W. H. Evers et al., Nano Lett. 13, 2317 (2013)], NC facets are atomically bonded, resulting in single-crystalline sheets, which, due to their nanogeometry, have an effective dimensionality below two. We predict electronic structures composed of successive bands formed by strong coupling between the wave functions of nearest-neighbor NCs. This coupling is mainly determined by the number of atoms at the NC bonding plane. The band structures deviate markedly from that of the corresponding two-dimensional (2D) quantum well; the 2D case can be recovered, however, if the effects of the nanogeometry are gradually reduced. The width of the bands can reach hundreds of meV, ascribing highly promising transport properties to square superlattices. The band edges are located at k=0 except for PbSe superlattices, where their position in k space surprisingly depends on the parity of the number of {100} atomic planes in the NCs. Our calculations demonstrate that semiconductors with dimensionality below two have a strong potential for (opto-)electronic, photovoltaic, and spintronic applications.
- Published
- 2013