Planar GaAs Nanowires on GaAs (100) Substrates: Self-Aligned, Nearly Twin-Defect Free, and Transfer-Printable

• Published in: Nano letters Vol. 8; no. 12; pp. 4421 - 4427
• Main Authors: Fortuna, Seth A, Wen, Jianguo, Chun, Ik Su, Li, Xiuling
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-12-2008
• Subjects: Catalytic methods; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wires; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Defect density; Temperature dependence; Gold; Gallium arsenides; Crystal defects; Epitaxial layers; Catalysts; Atmospheric pressure; Growth rate; Epitaxy; Nanophotonic device; Twinning; MOCVD; III-V compound; Operating conditions; Nanoelectronics; Transmission electron microscopy; Morphology; Growth mechanism; Nanowires; Nanostructured materials; Nanomaterial synthesis; Sacrificial layer; III-V semiconductors
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl802331m

We report the controlled growth of planar GaAs semiconductor nanowires on (100) GaAs substrates using atmospheric pressure metalorganic chemical vapor deposition with Au as catalyst. These nanowires with uniform diameters are self-aligned in direction in the plane of (100). The dependence of planar nanowire morphology and growth rate as a function of growth temperature provides insights into the growth mechanism and identified an ideal growth window of 470 ± 10 °C for the formation of such planar geometry. Transmission electron microscopy images reveal clear epitaxial relationship with the substrate along the nanowire axial direction, and the reduction of twinning defect density by about 3 orders of magnitude compared to III−V semiconductor nanowires. In addition, using the concept of sacrificial layers and elevation of Au catalyst modulated by growth condition, we demonstrate for the first time a large area direct transfer process for nanowires formed by a bottom-up approach that can maintain both the position and alignment. The planar geometry and extremely low level of crystal imperfection along with the transferability could potentially lead to highly integrated III−V nanoelectronic and nanophotonic devices on silicon and flexible substrates.