Herein, we present a straightforward and cost-effective
procedure
for producing conductive diamond tubes on the surface of porous carbon
nanotube hollow fibers using successive 10-pulsed laser annealing
shots and 6 h of hot filament chemical vapor deposition techniques.
Room-temperature Raman and X-ray diffraction spectra reveal the signature
T2g peaks near 1332.4 cm–1 and 111 planes
of diamonds near 43.9°, respectively. A low turn-on field (E
TO) ∼1.85 V/μm@1 μA/cm2 and a threshold field (E
TH) ∼2.54
V/μm@10 μA/cm2 were observed for the tubular
diamond structures. The field enhancement factor (β) was calculated
at 3594 and highly stable field emission current stability was observed
over a long period of 4 h. For the first time, a good insight into
the field emission results of the diamond is established with the
structural, electronic properties, and the work function (φ)
∼4.84 eV analysis conducted by the density functional theory
simulation. Finite electronic states at the Fermi level are observed
beyond a band gap, and it demonstrates the wide-band gap (4.4 eV)
semiconducting nature of the diamond. The Bader charge analysis and
maximum entropy method pattern revealed the negative electron affinity
of the diamond, and it is responsible for the emission of electrons
from the conduction band of the diamond. Besides, the accumulation
of charge carriers, which contributes to the electric field emission,
takes place due to the weak π bonds of carbon atoms. The low
turn-on field, the high field enhancement factor, and the good field
emission current stability of tubular diamond offer great prospects
for future efficient and low-cost field emission devices.