  The first investigation of the single-particle structure of the bound states
of 17C, via the d(16C, p) transfer reaction, has been undertaken. The measured
angular distributions confirm the spin-parity assignments of 1/2+ and 5/2+ for
the excited states located at 217 and 335 keV, respectively. The spectroscopic
factors deduced for these states exhibit a marked single-particle character, in
agreement with shell model and particle-core model calculations, and combined
with their near degeneracy in energy provide clear evidence for the absence of
the N = 14 sub-shell closure. The very small spectroscopic factor found for the
3/2+ ground state is consistent with theoretical predictions and indicates that
the {\nu}1d3/2 strength is carried by unbound states. With a dominant l = 0
valence neutron configuration and a very low separation energy, the 1/2+
excited state is a one-neutron halo candidate.
