Regensburg 2019 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 62: Direct-Write Nanofabrication and Applications III
(Electron Beam Induced Processing) (joint session DS/TT)

TT 62.8: Talk

Thursday, April 4, 2019, 17:30–17:45, H32

Effective protection of few-layer black phosphorus from reactive species generated by in-situ focused electron beam irradiation. — •Lobo Charlene and Elbadawi Christopher — School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo NSW 2007

Recent studies have shown that exposure of few-layer black phosphorus (FLBP) to reactive oxygen species (ROS) via photoactivated oxidation induces an immediate and permanent reduction in the electron and hole mobility of FLBP. Electron-beam irradiation in H2O vapour is known to generate ROS (such as *O2-, *OH and OH-) that are responsible for the degradation of FLBP in ambient environment, but FLBP stability has not been assessed during prolonged exposure to other gaseous environments.

Here, we study the stability of FLBP in H2O, O2, NF3 and NH3 environments using environmental scanning electron microscopy (ESEM) and in situ electrical conductance measurements. The electron beam is used both for ESEM imaging, and also to generate reactive species such as *O, *OH, *F and *H that can drive spatially-localized chemical reactions at the sample surface. Using this approach, we demonstrate two promising methods of protecting FLBP and other moisture-sensitive two-dimensional materials from degradation by ROS. Encapsulation of FLBP with ionic liquids dramatically slows the rate of degradation in ROS environments. FLBP degradation can also be prevented by maintaining the temperature in the range ~125-300 *C during ROS exposure, without requiring any protective coating.