Keyword Suggestions

Results
 
 
Account Login
 
 
 
 
 

Library Navigation

 
 

Browse Meetings

 
 
 
SS5.02 - Electronic Structure of Low Dimensional Chalcogenide-Based Superlattices Formed by Nanocrystals’ Oriented Attachment 
Date/Time:
April 23, 2014   2:00pm - 2:15pm
 
Speaker:
 
Taxonomy
 
 
 
Share:
 

Low dimensional semiconductors have been extensively investigated during the past few decades due to the abundance of their applications, such as transistors, solar cells, photo-detectors, light emitting diodes and lasers. An alternative perspective to this field, which is traditionally dominated by III-V and II-VI materials grown by gas phase methods in high vacuum, could stem from the oriented attachment of colloidal nanocrystals (NCs). The recently reported formation of chalcogenide-based, square or honeycomb superlattices through NCs oriented attachment [1] could open new pathways to the exploitation of low dimensional systems and hence necessitates determination of their electronic properties. In the current contribution, we present results of tight binding calculations on the electronic structure of single-crystalline sheets, with an effective dimensionality below two, and graphene- / silicene- like superlattices of PbSe or CdSe NCs [2, 3]. The primary role of both the atomic lattice and the overall geometry on the band structure is evident in all cases. The strong coupling between the wave functions of nearest-neighbor NCs, mainly determined by the number of atoms at the NCs bonding plane, results in electronic structures composed of successive bands. For single-crystalline sheets, band structures markedly differentiate from that of corresponding two-dimensional quantum wells, but the latter can be recovered if nanogeometry effects are gradually reduced. The enhanced width of the bands ascribes highly promising transport properties to square superlattices [2]. In the case of honeycomb lattices, which could combine the usual semiconductor properties with Dirac bands, unusual electronic properties are revealed. In rock-salt PbSe, the expected Dirac-type features are clouded by a complex band structure. However, in the case of zinc-blende CdSe, the honeycomb nanogeometry leads to band structures which comprise Dirac cones at two distinct energies and non-trivial flat bands in the conduction band whereas in the valence band several bands with topological edge states are present. These systems could serve as platforms for studying complex electronic phases starting from conventional semiconductors [3].Acknowledgment: This work has been supported by funding of the French National Research Agency (ANR-09-BLAN-0421-01)References[1] W. H. Evers et al., Nano Lett. 13, 2317 (2013)[2] E. Kalesaki et al., Phys. Rev. B 88, 115431 (2013)[3] E. Kalesaki et al., submitted
 


 
 
Average Rating: (No Ratings)
  Was great, surpassed expectations, and I would recommend this
  Was good, met expectations, and I would recommend this
  Was okay, met most expectations
  Was okay but did not meet expectations
  Was bad and I would not recommend this
 



Submit
 
Keynote Address
Panel Discussion - Different Approaches to Commercializing Materials Research
Business Challenges to Starting a Materials-Based Company
Fred Kavli Distinguished Lectureship in Nanoscience
Application of In-situ X-ray Absorption, Emission and Powder Diffraction Studies in Nanomaterials Research - From the Design of an In-situ Experiment to Data Analysis