Carbon ion irradiation effects on surface modifications and field emission properties of molybdenum

The effects of the carbon (C) ions irradiation on the compositional, structural, morphological and field emission (FE) properties of molybdenum (Mo) have been reported in this paper. The Mo samples were exposed to C ions at constant ion fluence of 2.8 x 10(13) ions/cm(2) and at different ion energies ranging from 400 to 800 keV using Pelletron Linear Accelerator. The ion range, electronic/nuclear energy losses and vacancies were estimated using SRIM/TRIM simulations. XRD patterns reveal no new phases. However, a significant lower angular peak shifting of preferred orientated Mo (110) plane was observed that strongly supports the variation in stacking fault probability (SFP) at higher ion energies of 700-800 keV. The definite trends in the crystallite size and dislocation line density except stresses were evaluated after the C ions irradiation. Surface features of ion irradiated Mo were explored by optical and scanning electron microscope (SEM), whereas work function and electrical conductivity were measured using scanning-kelvin-probe and four-probes, respectively. Field emission (FE) parameters of ion-structured Mo targets were also investigated under UHV by evaluating I-V characteristics accompanied by Fowler-Nordheim (F-N) plotting curves between current density (J) and applied electric field (E). The improved FE parameters such as turn-on field (E-o), maximum current density (J(m)(ax)) and field enhancement factor (beta) come out to be in the range of 2-35 V/mu m, 82-3250 and 8-33,970 nA/cm(2), respectively. The variation in FE properties is well correlated with morphological features, structural parameters, work function and electrical conductivity measurements.