Zincblende-to-wurtzite interface improvement by group III loading in Au-seeded GaAs nanowires

Achieving control of the crystal structure is essential in III-V nanowires, since twin defects, stacking faults and uncontrolled zincblende-wurtzite polytypism could have detrimental effects on the physical properties. In addition, precise control of the crystal phases also opens up the possibility of homomaterial bandgap engineering. Here, we show by ex situ chemical analysis of the alloy seed particle that Ga-rich conditions are required for growth of wurtzite GaAs nanowires using Au seed particles in MOVPE. Based on this understanding, we propose and demonstrate a growth procedure to significantly improve the crystal structure quality of the zincblende-to-wurtzite transition in GaAs nanowire heterostructures. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)