Both Fujifilm X100S and Fujifilm X100T have 16.0 MP resolution sensors but Fujifilm X100S's sensor is APS-C (23.6 x 15.8 mm ) and Fujifilm X100T's sensor is APS-C (23.6 x 15.8 mm ).
Since Fujifilm X100T's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Fujifilm X100S.
Another difference between these two cameras is that Fujifilm X100S's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the X100S and X100T sensor size comparison.
Fujifilm X100S and Fujifilm X100T have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.