Oxidation Resistant Germanium Nanowires: Bulk Synthesis, Long Chain Alkanethiol Functionalization and Langmuir-Blodgett Assembly

TL;DR

This paper presents a scalable synthesis of oxidation-resistant germanium nanowires, their surface functionalization with long-chain alkanethiols, and their assembly into Langmuir-Blodgett films for electronic applications.

Contribution

It introduces a simple bulk synthesis method for Ge nanowires, investigates surface passivation techniques, and demonstrates stable functionalization with long-chain alkanethiols.

Findings

Long-chain alkanethiols provide the most stable oxidation resistance.

Functionalized nanowires are soluble in organic solvents.

Assembled into Langmuir-Blodgett films for potential electronic use.

Abstract

A simple method is developed to synthesize gram quantities of uniform Ge nanowires (GeNWs) by chemical vapor deposition on preformed, monodispersed seed-particles loaded onto high surface area silica support. Various chemical functionalization schemes are investigated to passivate the GeNW surfaces using alkanethiols and alkyl Grignard reactions. The stability of functionalization against oxidation of germanium for various alkyl chain lengths is elucidated by X-ray photoelectron spectroscopy. Among all schemes tested, long chain alkanethiols (>=C12) are found to impart the most stable GeNW passivation against oxidation upon extended exposure to ambient air. Further, the chemically functionalized oxidation-resistant nanowires are soluble in organic solvents and can be readily assembled into close-packed Langmuir-Blodgett films potentially useful for future high performance electronic devices.