Impact of Ion Induced Changes on Field Emission in Multi-Walled Carbon Nanotubes

In the present paper, we have investigated the effects of low-energy argon (Ar) ion irradiation on the structural properties of multi-walled carbon nanotubes (MWCNTs) and their impact on field-emission (FE). The energy of Ar+ ions was kept constant at 1.2 keV, while the irradiation fluences were varied from 5 × 1015 to 1.6 × 1017 ions/cm2. The structural changes induced due to low-energy ion irradiation were studied by micro Raman spectroscopy. The effect of structural modifications of MWCNTs on their FE characteristics has also been investigated and found to be greatly influenced. After ion irradiation, the MWCNTs with open tips could perform better electron emitter with low turn-on and threshold fields of 1.3 and 3.2 V/µm, respectively. The mean field enhancement factor (β) increases from 3356 for a pristine sample to 9469 for ion-irradiated MWCNTs. Thus, the ion-irradiated MWCNTs show better FE properties, which could open up promising practical applications.