Effects of a shell on the electronic properties of nanowire superlattices.
We compute the structural and electronic properties of core-shell InAs/GaAs nanowire superlattices using Keating's valence force field and a sp3d5s* tight-binding model. We show that the GaAs shell limits strain relaxation but homogenizes the hydrostatic strain distribution in the InAs layers. This prevents the formation of a strain-induced well in the conduction band at the surface of the nanowires, which was shown to trap the electrons in thin InAs layers (Phys. Rev. B 2006, 74, 155304). The shell, however, enhances the piezoelectric field, which increases the separation between the electrons and holes in thick InAs layers. These results emphasize the intricate links between the structural and electronic properties of strained nanowire heterostructures.
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Département de Recherche Fondamentale sur la Matière Condensée, SP2M/L_Sim, CEA Grenoble, 38054 Grenoble Cedex 9, France.
D001152:Arsenicals / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D004553:Electric Conductivity; D004559:Electric Wiring; D005708:Gallium / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012666:Semiconductors; D013314:Stress, Mechanical; D013499:Surface Properties
D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium