Microwave-Assisted Solution Synthesized Germanium Nanocrystals

Ge is one of the quintessential semiconductors being considered in nanoform for optoelectronic applications. Ge alloys have been shown to have potential for energy storage as a Li ion battery anode and energy conversion as a catalyst. Ge has several advantages over Si or SiGe alloys including superior charge carrier mobilities, low dopant activation temperatures, and a smaller band gap. We have recently employed a two-step microwave-assisted reduction of GeI₄ in oleylamine to prepare monodispersed Ge NCs from 10 -20 nm in diameter. The as-synthesized Ge NCs showed high crystallinity with single crystal nature as indicated by powder X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscopy. Solutions involved in this two-step reaction were investigated with ¹H NMR spectroscopy and high-resolution mass spectrometry to better understand the reaction pathway. I will present new insights gained from this chemical route that may impact the nanoparticle synthesis of other covalently bonding semiconductors.