All Zinc-Blende GaAs/(Ga,Mn)As Core–Shell Nanowires with Ferromagnetic Ordering

• Published in: Nano letters 2013-04, Vol.13 (4), p.1572-1577
• Main Authors: Yu, Xuezhe, Wang, Hailong, Pan, Dong, Zhao, Jianhua, Misuraca, Jennifer, von Molnár, Stephan, Xiong, Peng
• Format: Article
• Language: English
• Subjects: Arsenicals - chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization; Devices; Droplets; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Ferromagnetism; Gallium - chemistry; Gallium arsenide; Gallium arsenides; Magnetic properties and materials; Magnets - chemistry; Materials science; Microscopy, Electron, Scanning; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanowires; Nanowires - chemistry; Order disorder; Particle Size; Physics; Quantum wires; Scanning electron microscopy; Semiconductors; Small particles and nanoscale materials; Specific phase transitions; Structural transitions in nanoscale materials; Studies of specific magnetic materials; Surface Properties; Temperature; Zinc - chemistry
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl304740k

Combining self-catalyzed vapor–liquid–solid growth of GaAs nanowires and low-temperature molecular-beam epitaxy of (Ga,Mn)As, we successfully synthesized all zinc-blende (ZB) GaAs/(Ga,Mn)As core–shell nanowires on Si(111) substrates. The ZB GaAs nanowire cores are first fabricated at high temperature by utilizing the Ga droplets as the catalyst and controlling the triple phase line nucleation, then the (Ga,Mn)As shells are epitaxially grown on the side facets of the GaAs core at low temperature. The growth window for the pure phase GaAs/(Ga,Mn)As core–shell nanowires is found to be very narrow. Both high-resolution transmission electron microscopy and scanning electron microscopy observations confirm that all-ZB GaAs/(Ga,Mn)As core–shell nanowires with smooth side surface are obtained when the Mn concentration is not more than 2% and the growth temperature is 245 °C or below. Magnetic measurements with different applied field directions provide strong evidence for ferromagnetic ordering in the all-ZB GaAs/(Ga,Mn)As nanowires. The hybrid nanowires offer an attractive platform to explore spin transport and device concepts in fully epitaxial all-semiconductor nanospintronic structures.