We investigated the effects of gamma irradiation doses of 50, 100, and 103 kGy on boron-doped diamond (BDD) thin films synthesized using microwave plasma-assisted chemical vapor deposition with varying boron concentrations of [B]/[C]gas = 100, 1000, 2000, and 4000 ppm. The diamond thin films were characterized prior to and post-irradiation and the influence was assessed in terms of morphology, structure, and physical properties using scanning electron microscopy, atomic force microscopy, x-ray diffraction, vibrational spectroscopy (Raman and IR), x-ray photoelectron spectroscopy, and electrical measurement techniques. The results clearly showed that the response of gamma irradiation on BDD films was distinctive compared to those of undoped diamond films with changes in electronic behavior from metallic (>1019 to 1020 cm–3) to semiconducting (≤1019 cm–3), especially in the case of heavily boron-doped diamond films demonstrated by micro-Raman spectroscopy and electrical property characteristics. In fact, this modification in electrical property behavior induced by “gamma conditioning” can be effectively used to fine control boron doping in chemically vapor deposited diamond much needed for various electronic devices. The “gamma conditioning” refers to material processing by radiation which helps to passivate electrically active boron and defects with hydrogen migration thus fine tunes the boron acceptor concentration albeit that this is difficult to achieve during BDD film deposition. In addition, the results also indicate that almost all of the BDD films studied hereby tend to reach a state of damage saturation when submitted to gamma irradiation of 103 kGy. We discuss our novel findings in terms of the interplay of boron-hydrogen in diamond with possible multiple scenarios: (i) the generation of point/Frenkel defects due to Compton scattered electrons, (ii) the formation of a nonmetallic boron-rich borocarbide (e.g., B13C2) phase, (iii) the passivation of electrically active acceptor (B) sites due to the invariable presence of H in the grains and at the grain boundaries, (iv) the desorption of H from the diamond surface, and (v) the “priming or pumping” effect, which improves the electronic properties by compensating for the shallow boron acceptors to produce semiconducting/insulating material, verified by the cold neutron depth profiling technique.

Carbon-based materials continue to attract attention because of their unique unsurpassable combination of physical properties thus offering multifunctionality. Included in this group of materials are numerous including HPHT diamond, low pressure chemical vapor deposited diamond thin films in multiple forms (poly-/micro-and nanocrystalline), nanostructured carbon, disordered tetrahedral carbon (DTC), micro-/nanocrystalline graphite, carbon nanotubes, as well as graphene. Among this family, diamond is a promising wide bandgap semiconductor with a large potential offering excitement and interest due to its unique blend of superlative physical (electronic, optical, mechanical, and chemical) properties [1]. Diamond and specifically doped-or impurity-incorporated diamond is of great interest for multiple applications such as for electrochemical micro-electrodes, high temperature, high power and frequency devices. Besides, it is reputed for being radiation hard thus predestined its usage in the development of radiation hard electronics over the existed semiconductors e.g. Si, GaAs, and AlGaN [2]. For space or extreme radiation environment applications such as deep UV photodiode (alternatively, visible blind), medical radiotherapy, and novel nuclear micro-battery [3][4][5][6], it is of utmost importance to demonstrate the influence of radiation on materials' structural integrity as well as physical stability. Since the structure dictate materials' physical properties, the assessment of physical properties provides a general guideline helping us to determine the nature of defects and/or structural modification induced due to radiation and its effect on the prototype device.