A photo detector device, comprising: a substrate layer; a plurality of doped semiconductor layers including a first semiconductor layer doped with a first dopant disposed above said substrate and a second semiconductor layer doped with a second dopant disposed above said first semiconductor layer and proximal thereto, wherein a doping density in said second semiconductor layer is less than a doping density in said first semiconductor layer; a first depletion region in said first semiconductor layer proximal to said second semiconductor layer; a second depletion region in said second semiconductor layer proximal to said first semiconductor layer; said first and second semiconductor layers (201, 202) being ion implanted in selected regions thereof and having an ion implantation profile in each of said first and second semiconductor layers at a generally positive lateral profile angle with respect to a normal to said first and second semiconductor layers (201, 202) so as to form a virtual mesa structure having angled side profiles in said first and second semiconductor layers (201, 202) and having an upwardly and inwardly narrowing shape according to said ion implantation profile; and said ion implantation profile further defining interior regions of said first and second semiconductor layers (201, 202) that are not ion implanted, and exterior regions of said first and second semiconductor layers (201, 202) that are ion implanted, said interior non-implanted region of the first semiconductor layer having a larger area than said interior non-implanted region of the second semiconductor layer; a virtual mesa depletion region in said virtual mesa structure, the virtual mesa depletion region comprising (a) a first depletion region in said first semiconductor layer proximal to said second semiconductor layer and (b) a second depletion region in said second semiconductor layer proximal to said first semiconductor layer, wherein a thickness of said virtual mesa depletion along said angled side profiles is greater than a thickness of said virtual mesa depletion in a center of said virtual mesa structure; and an electrical circuit coupled to said substrate and to any of said semiconductor layers (201, 202) so as to detect at least one incident photon in any of said semiconductor layers (201, 202) and to provide an electrical output corresponding to said detected one or more photons. a substrate layer; a plurality of doped semiconductor layers including a first semiconductor layer doped with a first dopant disposed above said substrate and a second semiconductor layer doped with a second dopant disposed above said first semiconductor layer and proximal thereto, wherein a doping density in said second semiconductor layer is less than a doping density in said first semiconductor layer; a first depletion region in said first semiconductor layer proximal to said second semiconductor layer; a second depletion region in said second semiconductor layer proximal to said first semiconductor layer; said first and second semiconductor layers (201, 202) being ion implanted in selected regions thereof and having an ion implantation profile in each of said first and second semiconductor layers at a generally positive lateral profile angle with respect to a normal to said first and second semiconductor layers (201, 202) so as to form a virtual mesa structure having angled side profiles in said first and second semiconductor layers (201, 202) and having an upwardly and inwardly narrowing shape according to said ion implantation profile; and said ion implantation profile further defining interior regions of said first and second semiconductor layers (201, 202) that are not ion implanted, and exterior regions of said first and second semiconductor layers (201, 202) that are ion implanted, said interior non-implanted region of the first semiconductor layer having a larger area than said interior non-implanted region of the second semiconductor layer; a virtual mesa depletion region in said virtual mesa structure, the virtual mesa depletion region comprising (a) a first depletion region in said first semiconductor layer proximal to said second semiconductor layer and (b) a second depletion region in said second semiconductor layer proximal to said first semiconductor layer, wherein a thickness of said virtual mesa depletion along said angled side profiles is greater than a thickness of said virtual mesa depletion in a center of said virtual mesa structure; and an electrical circuit coupled to said substrate and to any of said semiconductor layers (201, 202) so as to detect at least one incident photon in any of said semiconductor layers (201, 202) and to provide an electrical output corresponding to said detected one or more photons.