Infrared thermal detectors versus photon detectors: I. Pixel performance

Investigations of the performance of IR thermal detectors as compared to photon detectors are presented. Due to fundamental different types of noise, these two classes of detectors have different dependencies of detectivities on wavelength and temperature. The photon detectors are favored at long wavelength IR and lower operating temperatures. The thermal detectors are favored at very long wavelength spectral range. The comparative studies of the thermal detectors with HgCdTe photodiodes, doped silicon detectors and quantum well IR photodetectors are carried out. In comparison with Kruse's paper these studies are re-examined taking into account updated theories of different types of detectors. The considerations are made for different background levels.