In As/GaAs Core-Shell Nanowires

Gold-assisted vapor-liquid-solid (VLS) growth of In As nanowires was optimized and used for growth of highly mismatched InAs/GaAs core-shell heterostructure nanowires having the wurtzite structure. The motivation is 2-fold, providing means for surface passivation of In As nanowires (NWs) for electronic devices and ballistic transport applications on one hand and for studying the structural properties of a highly mismatched system in a core-shell, cylindrical configuration on the other hand. The misfit between the In As core and the mostly relaxed GaAs shell was deduced from the average spacing between the edge dislocations, the periodicity of the Moire fringes resulting from the overlap between the In As and GaAs lattices and the splitting in the electron diffraction images. Both line and loop edge dislocations are formed in the strain relaxation process. The experimental radial and axial misfits were found to be approximately 6 +/- 1% and 4 +/- 0.5%, respectively.