A bio-inspired imaging device mimicking visual adaptation of human vision provides a large dynamic range in imaging an image. The device employs a neuromorphic vision sensor realized with phototransistors each being a field-effect transistor, a channel layer of which is an atomically-thin layer of two-dimensional semiconductor material. The channel layer is intentionally formed with defects trap states for trapping a portion of charge carriers generated by a light beam incident on the phototransistor such that intensity information of the light beam is memorized. A gate-source voltage directs the defects trap states to de-trap the trapped portion of charge carriers or to further trap an additional portion of charge carriers, allowing the phototransistor to exhibit a time-dependent excitation or inhibition effect on drain current to thereby enable the imaging sensor to mimic scotopic or photopic adaptation in imaging the image.

A semiconductor-graphene heterojunction quad-detector pairs a semiconductor material with curved graphene strips in a quad-cell design. Graphene has been shown to have exceptional electrical properties that enhance the operation of semiconductor photodetectors. These properties address limitations of current semiconductor quad-cell devices by drastically increasing their sensitivity. According to an aspect of the present disclosure, a position detector includes a substrate having windows formed therein. Four graphene pads each having a plurality of curved strips are formed on the substrate. Each of the plurality of curved strips have a first end connected to a grounded conductor pad and a second end connected to one of four signal conductor pads.