An imaging device formed as an active pixel array combining a CMOS fabrication process and a nanowire fabrication process. The pixels in the array may include a single or multiple photogates surrounding the nanowire. The photogates control the potential profile in the nanowire, allowing accumulation of photo-generated charges in the nanowire and transfer of the charges for signal readout. Each pixel may include a readout circuit which may include a reset transistor, charge transfer switch transistor, source follower amplifier, and pixel select transistor. A nanowire is generally structured as a vertical rod on the bulk semiconductor substrate to receive light energy impinging onto the tip of the nanowire. The nanowire may be configured to function as either a photodetector or a waveguide configured to guild the light to the substrate. Light of different wavelengths can be detected using the imaging device.