Spectral analysis of the emission current noise exhibited by few layer WS2 nanosheets emitter

Spectral analysis of the field emission (FE) current fluctuations has been carried out at the base pressure ~1×10−8 mbar. The emission current stability investigated at preset value of 2 µA is characterized by ‘step’ like fluctuation. The spectral analysis performed on a FFT (Fast Fourier Transform) analyzer revealed that the observed noise is of 1/fα type, with the value of α as ~1.05. The estimated value of α implies that the current fluctuations are mainly due the various processes occurring on atomic scale like adsorption, migration, and/or desorption of the residual gas species on the emitter surface.