201492.fig.005a
(a)
201492.fig.005b
(b)
201492.fig.005c
(c)
201492.fig.005d
(d)
Figure 5: XPS spectra of (a) O 1s, (b) Ti 2p, (d) Ga 3d photoelectrons in undoped and Ga-doped TiO2 nanoparticles. (c) Deconvolution of Ti 2p peaks of doped samples to show the existence of Ti+4 and Ti+3 ions.