The Growth of One‐Dimensional Single‐Crystalline AlN Nanostructures by HVPE and Their Field Emission Properties

Single‐crystalline AlN nanostructures, such as thin films, nanoneedles, nanocolumns, and nanowires, depending on the controlled gas‐flow ratio, are synthesized by halide vapor‐phase epitaxy (HVPE). In comparison with a typical vapor/liquid/solid (VLS) mechanism for the growth of nanowires, well‐aligned AlN nanorod arrays with diameters below 20 nm are grown on a catalyst‐free Si substrate though a vapor/solid (VS) mechanism. Their structural and optical properties are measured by X‐ray diffraction (XRD), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and photoluminescence (PL). In particular, AlN nanorods exhibit an excellent field emission property with a low turn‐on field of 2.25 V µm−1. The field enhancement factor is estimated to be about 784 due to well‐aligned, needle‐shaped, AlN nanorods.