We
can see that the upper position of the valence band has major influence
after doping. Furthermore, the O-p states and s-DOS on either side the
Fermi stage tend to be sharpen by the O atom after Ag doping in present
lattice. Fig 3 (a) shows the PDOS of pure SrTiO3 and
Ag-doped SrTiO3 we observed that the value of Ag-doped
SrTiO3 is maximum as compared to pure
SrTiO3. The elemental PDOS was plotted to compare the
pure and doped systems Fig 3 (b & e) that exhibit major differences in
valance and conduction band states before doping and after doping. Fig 3
(c) shows the PDOS of pure and Ag-doped Ti, we observed that value of
Ag-doped Ti is greater as compare to pure Ti. Fig 3 (f) shows the TDOS
and for pure and Ag-doped SrTiO3, we see that the top at
the valence band is in the limit of 0 to 5 electron Volt generates deep
effect, according to the TDOS, due to recently emerging Ag-d states. By
appearance the Ag- d states at the upper point of the valence band at
point G could explained an upper change in the valance band. As a
result, we claimed that Ag doping in SrTiO3 has two
significant consequences. The first shows the reduction in band gap
reasoned of inclusion of Ag in SrTiO3. Second, we see
alter in structure of the band gap after doping from indirect to direct.
As a result, Ag doped SrTiO3 would be much effective for
optical devices [17,18].