Enhancement of electrical conductivity and microplasma illumination properties of boron doped diamond films by Ni-ion implantation and annealing processes

Abstract

This study explores the enhancement of microplasma illumination (MI) characteristics of boron-doped diamond (BDD) films by nickel-ion implantation and annealing processes. Ni-ions are implanted in BDD films, which facilitate the formation of amorphous carbon (a-C) at the grain boundaries of BDD films leading to an electrical conductivity of 7.6 × 104 S/cm. Upon annealing, the a-C phases are converted into sp2-bonded nanographitic phases at the grain boundaries, developing conduction channels for effectual transport of electrons, which enhances the film's electrical conductivity to 1.0 × 105 S/cm. Interestingly, the Ni-ion implanted and annealed BDD (Ni-BDDA) films exhibit a high density of electron emission sites, reaching a peak current of approximately 9.0 nA. Moreover, the Ni-BDDA films are successfully used as cathode in the MI devices, where a low breakdown voltage of 370 V with an improved MI current density of 5.8 mA/cm2, and an extended lifetime stability of 784 min. These findings underscore the role of Ni-ion implantation and annealing processes in the formation of sp2-nanographitic phases at the grain boundaries of Ni-BDDA films, resulting in the development of an electrically conducting cathode material for high-performance microplasma illumination devices.