Surface Hydrogen Enables Subeutectic Vapor-Liquid-Solid Semiconductor Nanowire Growth.

Vapor-liquid-solid nanowire growth below the bulk metal-semiconductor eutectic temperature is known for several systems; however, the fundamental processes that govern this behavior are poorly understood. Here, we show that hydrogen atoms adsorbed on the Ge nanowire sidewall enable AuGe catalyst supercooling and control Au transport. Our approach combines in situ infrared spectroscopy to directly and quantitatively determine hydrogen atom coverage with a "regrowth" step that allows catalyst phase to be determined with ex situ electron microscopy.

High-throughput electrical measurement and microfluidic sorting of semiconductor nanowires.

Existing nanowire electrical characterization tools not only are expensive and require sophisticated facilities, but are far too slow to enable statistical characterization of highly variable samples. They are also generally not compatible with further sorting and processing of nanowires. Here, we demonstrate a high-throughput, solution-based electro-orientation-spectroscopy (EOS) method, which is capable of automated electrical characterization of individual nanowires by direct optical visualization of their alignment behavior under spatially uniform electric fields of different frequencies.

Solid-Liquid-Vapor Etching of Semiconductor Nanowires.

The vapor-liquid-solid (VLS) mechanism enables the bottom-up, or additive, growth of semiconductor nanowires. Here, we demonstrate a reverse process, whereby catalyst atoms are selectively removed from the eutectic catalyst droplet. This process, which is driven by the dicarbonyl precursor 2,3-butanedione, results in axial nanowire etching.