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/f^α 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.