Observation of field emission from GeSn nanoparticles epitaxially grown on silicon nanopillar arrays

We apply molecular beam epitaxy to grow GeSn-nanoparticles on top of Si-nanopillars patterned onto p-type Si wafers. We use x-ray photoelectron spectroscopy to confirm a metallic behavior of the nanoparticle surface due to partial Sn segregation as well as the presence of a superficial Ge oxide. We report the observation of stable field emission (FE) current from the GeSn-nanoparticles, with turn on field of $65\,\,{\rm{V}}\,\mu {{\rm{m}}}^{-{\rm{1}}}$ and field enhancement factor ? ~ 100 at anode-cathode distance of ~0.6 ?m. We prove that FE can be enhanced by preventing GeSn nanoparticles oxidation or by breaking the oxide layer through electrical stress. Finally, we show that GeSn/p-Si junctions have a rectifying behavior