  Using angle-resolved photoelectron spectroscopy, we compare the electronic
band structure of an ultrathin (1.8 nm) {\delta}-layer of boron-doped diamond
with a bulk-like boron doped diamond film (3 {\mu}m). Surprisingly, the
measurements indicate that except for a small change in the effective mass,
there is no significant difference between the electronic structure of these
samples, irrespective of their physical dimensionality. While this suggests
that, at the current time, it is not possible to fabricate boron-doped diamond
structures with quantum properties, it also means that nanoscale doped diamond
structures can be fabricated which retain the classical electronic properties
of bulk-doped diamond, without a need to consider the influence of quantum
confinement.
