Single-photon detectors, arrays of single-photon detectors, methods of using the single-photon detectors and methods of fabricating the single-photon detectors are provided. The single-photon detectors combine the efficiency of a large absorbing volume with the sensitivity of nanometer-scale carrier injectors, called “nanoinjectors”. The photon detectors are able to achieve single-photon counting with extremely high quantum efficiency, low dark count rates, and high bandwidths.