A study was made of vertically aligned AlAs/GaAs/GaP heterostructure nanowires grown onto a Si substrate. The nanowires were grown using Au colloidal nanoparticles as catalysts in vapor–liquid–solid mode. By alternately changing the source material between Ga and Al, GaAs/AlAs/GaAs/AlAs/GaAs nanowires were grown having a well-controlled periodic structure and composition on a GaP segment which was epitaxially deposited onto a Si substrate. No dislocations introduced by the lattice mismatch were found in the GaAs segment of the nanowires grown onto the GaP segment; in spite of a lattice mismatch as large as 4%. This was because the nanowires had a particular columnar structure with nanoscale diameter and could relax laterally to accommodate the high strain. Stacking faults existed in zincblende-structured GaP and GaAs segments, while the AlAs segment had a purely wurtzite crystal structure with no stacking faults. The stacking fault in III–V nanowires was significantly dependent upon the stacking-fault energy and ionicity. With increasing ionicity, the stacking faults could be more easily introduced and these nanowires tended to have a wurtzite structure.

Structural, Compositional, and Optical Characterizations of Vertically Aligned AlAs/GaAs/GaP Heterostructure Nanowires Epitaxially Grown on Si Substrate. G.Zhang, K.Tateno, H.Gotoh, T.Sogawa, H.Nakano: Japanese Journal of Applied Physics, 2010, 49[1], 015001