Abstract: An improved low voltage, small surface area, high signal-to-noise ratio photo gate includes a layer of photoreceptive semiconductor material having an impurity concentration selected to enhance the formation of hole electron pairs in response to photons impinging on a surface of the substrate, an electrode extending from the surface of the substrate into the substrate a substantial distance; an insulating layer disposed between the electrode and the substrate for electrically insulating the electrode from the substrate; so that upon the application of an electrical potential to the electrode, a potential well is formed in the substrate surrounding the electrode for accumulating charge generated when photons impinge on the surface of the substrate surrounding the electrode.