a plurality of unit pixels,

wherein each of the unit pixels is structured to respond to incident light to produce photocharges indicative of detected incident light and includes:

sub-pixels, each sub-pixel including a control region configured to generate, within a substrate in which the sub-pixels are disposed, a current that carries the photocharges; and

a detection region spaced from the control region and configured to capture the photocharges carried by the current;

a plurality of first isolation portions disposed between two adjacent sub-pixels;

a second isolation portion disposed to surround the sub-pixels; and

a voltage applying region disposed at a center portion of the unit pixel and configured to receive a first voltage.