Abstract: An infrared photodetector containing a region of semiconductor quantum dots (1), n type doped in the barrier region (2), and sandwiched between respective layers of semiconductors of n type (3) and p type (4). When infrared photons (5) are absorbed, they create electronic transitions (6) from the confined states in the dots (7) to the conduction band (8). This causes the appearance of a voltage between device p (9) and n (10) contacts or the production of an electrical current. In either way, the detection of the infrared light is possible. A low band-pass filter (12) prevents high energy photons (13) from entering the device and causing electronic transitions (14) from the valence (15) band to the conduction band (8).