Germanium arsenide nanosheets applied as twodimensional field emitters

The IV-V groups binary compound germanium arsenide (GeAs) is a semiconductor that can be easily exfoliated in very thin nanosheets and is characterized by a band gap ranging from 0.6 eV (bulk form) up to 2.1 eV (monolayer). We investigate the field emission characteristics of exfoliated multilayer GeAs nanosheets by means of a tip-anode setup, where a nanomanipulated W-tip is positioned in front of the GeAs emitting layer at nanometric distance, all controlled inside a scanning electron microscope. We demonstrate that GeAs multilayers are suitable to develop electron sources, with turn-on field of the order of 102Vμm-1, and field enhancement factor of about 70.