Both Nikon D7000 and Samsung Galaxy Camera 2 have 16.0 MP resolution sensors but Nikon D7000's sensor is APS-C (23.6 x 15.7 mm ) and Samsung Galaxy Camera 2's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Nikon D7000'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 Samsung Galaxy Camera 2.
Below you can see the D7000 and Galaxy Camera 2 sensor size comparison.
As seen above, Nikon D7000 has a 13.2x Larger sensor area than Samsung Galaxy Camera 2. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.