An image sensor (101; 102), comprising: a semiconductor substrate having a first surface and a second surface opposite to the first surface in a vertical direction; a first isolation structure disposed in the semiconductor substrate for defining pixel regions in the semiconductor substrate; at least one visible light detection structure disposed in the semiconductor substrate; at least one infrared light detection structure disposed in the semiconductor substrate, wherein the at least one visible light detection structure and the at least one infrared light detection structure are disposed within one of the pixel regions, and a first portion of the at least one visible light detection structure is disposed between the at least one infrared light detection structure and the second surface of the semiconductor substrate in the vertical direction; wherein the image sensor further comprises: a first gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one infrared light detection structure; and a second gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one visible light detection structure; and characterised by a reflective structure, in particular an electrically floating conductive structure, disposed on the first surface of the semiconductor substrate, wherein a part of the reflective structure is disposed on the first isolation structure in the vertical direction, and another part of the reflective structure is disposed between the first gate electrode and the second gate electrode. a semiconductor substrate having a first surface and a second surface opposite to the first surface in a vertical direction; a first isolation structure disposed in the semiconductor substrate for defining pixel regions in the semiconductor substrate; at least one visible light detection structure disposed in the semiconductor substrate; at least one infrared light detection structure disposed in the semiconductor substrate, wherein the at least one visible light detection structure and the at least one infrared light detection structure are disposed within one of the pixel regions, and a first portion of the at least one visible light detection structure is disposed between the at least one infrared light detection structure and the second surface of the semiconductor substrate in the vertical direction; wherein the image sensor further comprises: a first gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one infrared light detection structure; and a second gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one visible light detection structure; and characterised by a reflective structure, in particular an electrically floating conductive structure, disposed on the first surface of the semiconductor substrate, wherein a part of the reflective structure is disposed on the first isolation structure in the vertical direction, and another part of the reflective structure is disposed between the first gate electrode and the second gate electrode. a first gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one infrared light detection structure; and a second gate electrode disposed on the first surface of the semiconductor substrate and disposed corresponding to the at least one visible light detection structure; and characterised by a reflective structure, in particular an electrically floating conductive structure, disposed on the first surface of the semiconductor substrate, wherein a part of the reflective structure is disposed on the first isolation structure in the vertical direction, and another part of the reflective structure is disposed between the first gate electrode and the second gate electrode.