  Electron-doped TiNCl is a superconductor, for which exotic mechanisms of the
superconductivity have been discussed. However, difficulty in preparing large
single-phase samples has prevented the direct observation of its electronic
structure and how that changes with electron doping. In this study,
micro-photoemission spectroscopy ({\mu}-PES) was used to reveal the electronic
structures of TiNCl and Na-intercalated TiNCl (Na-TiNCl). Comparison of Ti 2p
core-level spectra shows the enhancement of a spectral feature in Na-TiNCl that
suggests an increase in its metallic character. This indicates the introduction
of electron carriers to the TiNCl layers. Although the overall valence band
electronic structure of parent TiNCl could be reproduced by first-principle
calculations, that of Na-TiNCl showed a marked deviation from the rigid band
model near the Fermi level (EF). The spectral shape observed near EF of
Na-TiNCl was found to be similar to a result in early transition metal oxides
that has been attributed to the effect of strong electron correlation. The
present study also demonstrated the usefulness of {\mu}-PES to obtain reliable
electronic structure data for samples that are difficult to make at large
sizes.
