Photo-assisted field emission and current noise analysis from single submicron CdS wire

A single crystalline CdS submicron wire has been synthesized by simple thermal evaporation route. A non-linear and linear F-N plots have been observed for the single submicron CdS wire and multiple nanowires, respectively. The observed non-linearity can be attributed to the band structure of CdS. We believe that at low electric field electron emission is believed to be from the conduction band and at high field values, the field emission is a contribution from both the conduction as well as the valence band. Single submicron CdS wire is seen to exhibit photo assisted field emission behavior upon visible light illumination. The photo-enhanced field emission current is found to switch rapidly between the preset to five times the preset value. The field emission current noise analysis has also been investigated using a Fast Fourier Transform analyzer. The current-time traces show step like fluctuations, with 1/f^α type of power spectrum. The observed fluctuations in the field emission current are attributed to the various processes at the emitter surface and intrinsic band structure of CdS.