Both Nikon D80 and Samsung SL102 have 10.0 MP resolution sensors but Nikon D80's sensor is APS-C (23.6 x 15.8 mm ) and Samsung SL102's sensor is 1/2.3-inch (6.08 x 4.56 mm ).
Since Nikon D80'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 SL102.
Below you can see the D80 and SL102 sensor size comparison.
As seen above, Nikon D80 has a 13.5x Larger sensor area than Samsung SL102. 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.