Details

Autor(en) / Beteiligte

• Jiang, Nian
• Wong-Leung, Jennifer
• Joyce, Hannah J
• Gao, Qiang
• Tan, Hark Hoe
• Jagadish, Chennupati

Titel

Understanding the True Shape of Au-Catalyzed GaAs Nanowires

Ist Teil von

• Nano letters, 2014-10, Vol.14 (10), p.5865-5872

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• With increasing interest in nanowire-based devices, a thorough understanding of the nanowire shape is required to gain tight control of the quality of nanowire heterostructures and improve the performance of related devices. We present a systematic study of the sidewalls of Au-catalyzed GaAs nanowires by investigating the faceting process from the beginning with vapor–liquid–solid (VLS) nucleation, followed by the simultaneous radial growth on the sidewalls, and to the end with sidewall transformation during annealing. The VLS nucleation interface of our GaAs nanowires is revealed by examining cross sections of the nanowire, where the nanowire exhibits a Reuleaux triangular shape with three curved surfaces along {112}A. These curved surfaces are not thermodynamically stable and adopt {112}A facets during radial growth. We observe clear differences in radial growth rate between the ⟨112⟩A and ⟨112⟩B directions with {112}B facets forming due to the slower radial growth rate along ⟨112⟩B directions. These sidewalls transform to {110} facets after high temperature (>500 °C) annealing. A nucleation model is proposed to explain the origin of the Reuleaux triangular shape of the nanowires, and the sidewall evolution is explained by surface kinetic and thermodynamic limitations.