Abstract: The present invention relates to a novel photo-detector structure and method whereby light is detected in a semiconductor substrate. Through the use of a small current of majority carriers an electrical field is created that directs photo-generated minority carriers towards a detection region. In this way, a large sensitive area 34 for a detector can be designed with a detection region having low junction area and low associated detector capacitance, thus enhancing output signal to noise ratio and/or speed of attached readout circuits. Simultaneously, the assistant majority current can sweep the minority carriers from deep within the substrate towards the detection region, thus improving the overall detector sensitivity. By making the majority current reconfigurable, a photonic mixer structure with two or more detection regions can be conceived, whereby the direction of the applied current will determine in an efficient way to which detection region the photo-generated minority carriers will be directed.