the present disclosure provides systems and methods for configuring and constructing a single photo detector or array of photo detectors with all fabrications circuitry on a single side and an architecture that enables the laser step to be the final step or a late step in the fabrication process . both the anode and the cathode contacts of the diode are placed on a single side , while a layer of laser treated semiconductor is placed on the opposite side for enhanced cost - effectiveness , photon detection , and fill factor .