  By adjusting the incidence angle of incoming X-ray near the critical angle of
X-ray total reflection, the photoelectron intensity is strongly modulated due
to the variation of X-ray penetration depth. Photoelectron spectroscopy (PES)
combining with near total reflection (NTR) exhibit tunable surface sensitivity,
providing depth-resolved information. In this review article, we first describe
the experimental setup and specific data analysis process. We then review three
different examples which show the broad application of this method. The
emphasis is on its applications to correlated oxide heterostructures,
especially quantitative depth analyses of compositions and electronic states.
In a last part, we discussed the limitations of this technique, mostly in terms
of range of samples which can be studied.
