Low-Frequency Noise Spectroscopy Characterization of HgCdTe Infrared Detectors

Low-frequency noise spectroscopy (LFNS) is an effective tool to study the trap properties in infrared photodetectors which may cause the limitations of dark current, dark noise, and quantum efficiency as well. In this article, the trap levels of HgCdTe infrared detectors with different Cd compositions are investigated with LFNS. The defect levels within the bandgap have been identified. In addition, trap states with activation energy above the material bandgap are also found for Hg-vacancy doped mid-wavelength and long-wavelength infrared HgCdTe photodetectors due to the resonant states located above the conduction band edge. The method to eliminate these resonant states is also investigated.