Environmental instability of few-layer black phosphorus

We study the environmental instability of mechanically exfoliated few-layer black phosphorus (BP). From continuous measurements of flake topography over several days, we observe an increase of over 200% in volume due to the condensation of moisture from air. We find that long term exposure to ambient conditions results in a layer-by-layer etching process of BP flakes. Interestingly, flakes can be etched down to single layer (phosphorene) thicknesses. BP's strong affinity for water greatly modifies the performance of fabricated field-effect transistors (FETs) measured in ambient conditions. Upon exposure to air, we differentiate between two timescales for doping of BP FET transfer characterisitcs: a short…

• EC
  European Commission
• FF
  Foundation for Fundamental Research on Matter